Some sentences

1.Can you tell me where he lives now？
2.I hope that you can get along with the classmates. (Or "your classmates")
3.It is raining hard. I will wait for it to stop and then I will leave.
4.No matter what he says, I don't believe him.
5.My mother spends an hour cleaning the house everyday.
6.He said that he took a number of pictures. (Technically correct but most people say "he took many pictures.")
7.Her parents tell her not to go out alone at night.
8.I would rather buy a new computer than a used one. (The second use of "buy" is unnecessary)
9.When I got to the checkout, I realized I forgot my wallet at home. (Very good, but remember to always capitalize the word I)
10.No matter how difficult it is, I will never give up.
11.Drink more water, it is good for your health.
12.The key is made of metal and used for locking the door.
13.You want to take back your mobile phone, don't you？
14.I don't think he will attend the meeting tomorrow.
15.Although I'm not rich, I will try my best to help you.
16.Now that you are already a adult, you should know what to do.
17.Although his daughter is very mischievous, she knows how to behave when they have guests in their home.
18.If I think up the method, I will not let you to help me. (I'm not certain what you mean here but the grammar is correct)
19.Although it is difficult, we will have a brave face.
20.Make sure all windows are closed before you go to sleep.

Some sentences

1.Can you tell me where is he reside in now？

The correction version is, "Can you tell me where he is residing now?"

However, a naive speaker would ask, "Can you tell me where he is living now?"

2.I hope that you can get along with your classmates.

3.It is raining heavily,  I just can am waiting for it to stop so that I'm I can leave.

4.No  matter he say anything,  i  I  don't believe him.

The expression we use is, "No matter what he says, I don't believe him."

5.My mother spends an hour to clean up the house everyday.

It is a little more natural to write, "My mother spends an hour every day to clean the house."

6.He said that he took a number of pictures.

7.He Her parents tell her do not go out alone at night.

If you are quoting what the parents say, you must use punctuation:

Her parents tell her, "Do not go out alone at night."

If you are not quoting what the parents say, you need to change the sentence slightly.

Her parents tell her to not go out alone at night.

8.I would rather buy a new computer than buy a used one.

9.When  I  got to the checkout,  I  realized  I  forgot left my wallet at home.

You last phrase could be either of these:

"I realized I left my wallet at home."

"I realized I forgot my wallet."

10.No matter it is how difficult it is,  I will never give up.

Some sentences

1.Can you tell me where is he residing in now？
2.I hope that you can get along with your classmates.
3.It is raining heavily,_I just can am waiting for it to stop so that I'm can leave.
4.No_matter what he says/said, say anything,I don't believe him.
5.My mother spends an hour in house cleaning up the house everyday.
6.He said that he took a number of pictures.
7.Her parents tell her do not go out alone at night.
8.I would rather buy a new computer than buy a used one.
9.When I 非大写不可 got to the checkout,_I realized that I forgot left my wallet at home.
10.No matter it is how difficult it is,_I will never give up.
11.Drink more water! It is good for your health.
12.The key is made of metal and is used for locking the door. 或者 ... and is used to lock the door.
13.You want to take back your mobile phone,_don't you？
14.I think he will not attend the meeting tomorrow.
15.Although I'm not rich,_but I will try my best to help you.
16.Now that you are already a adult,_you should know what you should/ought/have/must/can/ do.
17.Although his daughter is very mischievous,_but 不許有 "but" 在 "although" 之後, 不与中文的 "雖然 ... 不過/但是" she knows how to do behave when the guests are around at home.
18.If I can think up the of a method,_Ii will not let you to need your help me. 你的写法沒有人情味
19.Although it is beset with difficulty,_we will be have to put up with a brave to face.
20.Make sure all windows are closed before you going to sleep.

11.Drink more water,  it is good for your health. 

12.The key is made of metal and used for locking the door.

13.You want to take back your mobile phone,  don't you？

14.I think he will not attend the meeting tomorrow.

15.Although I'm not rich,but i will try my best to help you.

In this context, "although" and "but" mean the same thing, so you only need one:

"Although I am not rich, I will try my best to help you."

"I am not rich, but I will try my best to help you."

16.Now that you are already an adult,  you should know what you do.

17.Although his daughter is very mischievous,  but she knows how to do behave when the guests are at home.

18.If  i  I  think up the method,   i  I  will not let you to help me.

19.Although it is beset with difficulties,  we will be brave to and face the situation.

20.Make sure all windows are closed before you going go to sleep.

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Please be careful with punctuation.  If you improve your punctuation, it will greatly improve to your English.

Some sentences

1.Can you tell me where is he reside in now？
2.I hope that you can get along with classmates.
3.It is raining heavily,I just can waiting for it to stop that I'm leave.
4.Nomatter he say anything,i don't believe him.
5.My mother spend an hour clean up the house everyday.
6.He said that he took a number of pictures.
7.His parents tell him do not go out alone at night.
8.I would rather buy a new computer than buy a used one.
9.When i got to the checkout,i realized i forgot my wallet at home.
10.No matter it is how difficult,I will never give up.
11.Drink more water,it is good for your health.
12.The key is made of metal and used for lock door.
13.You want to take back your mobile phone,don't you？
14.I think he will not attend the meeting tomorrow.
15.Although I'm not rich,but i will try my best to help you.
16.Now that you are already a adult,you should know what you do.
17.Although his daughter is very mischievous,but she knows how to do when the guests at home.
18.If i think up the method,i will not let you to help me.
19.Although it is beset with difficult,we will be brave to face.
20.Make sure all windows are closed before you going to sleep.