Are these sentence correct grammatically?

Correction: In Yellow

Usually, "非常" doesn't come after "为什么". It's like asking, Why is your house very messy? Like in english, we say, Why is your house so messy? Then, we add "的" to somewhat complete the adjective of "乱七八糟".

A more natural saying would be: 你的房子怎么那么乱？(lit. How is your house this messy?)

2. 你终于找工作了吗？
Not sure if you are saying, "Are you finally looking for a job?" : 你终于开始找工作了吗？"开始" to say that the person has started looking for a job.
or "Have you finally found a job?" : 你终于找到工作了吗? The "到" is important here, to say that the person "has found" the job.

3. 什么发生你的圣体？
This isn't grammatically correct.
If you are trying to ask what happened, "发生了什么事" (lit. what happened?) or "怎么会这样" (lit. how did it become like this) would suffice.
If you are trying to ask if someone is feeling okay, we usually just say "身体没事吧" or "身体还好吧"？Both mean "Is your body okay?" literally, but can also mean "How are you feeling?"

4. 为什么你放餐具？
To "放餐具" is to put them, literally. But if you are trying to say that someone is placing them nicely on the table (preparing for dinner perhaps?), then it should be 摆餐具。

你怎么摆餐具？

5. 她忽然来这里你觉得什么发生？
Here are some natural sayings.

她忽然来这里，你觉得会是什么事？ (Lit. What do you think is the reason she's here for?)
她忽然来这里的原因是什么？(Lit. What's the reason she's here?)
她忽然来这里，是不是发生了什么事？(Lit. She's here, did something happen?)

6. 我们还有灰尘在天河黑篮吗？
No idea, sorry. 

7. 他去过道处！你觉得他工作在哪里？
他哪都去过了！你觉得他工作在哪里？

8. 你可以放垃圾在垃圾桶吗？
你可以把垃圾丢进垃圾桶里吗？

放 is to put. But when using 垃圾桶 (the bin), we say 丢进. And when there's 进, we need to add 里 so it makes sense. 进 and 里 comes together like "go" and "into". To go into something, go inside something.

9. 你可以换我的电话资料吗？
If you want to get someone's number, “你可以和我交换电话号码吗？” would be grammatically correct. But pick up lines work better nowadays :D

10. 学生的工具是什么？
No idea, sorry. 

11. 为什么吸烟对圣体不好？
为什么吸烟对身体不好？

12. 你在你的书房有机半数？
No idea, sorry. 

13. 你可以叫一个伊朗的教授吗？
No idea, sorry. 

14. 你喜欢吃什么在零食？
你喜欢吃什么零食？

15. 为什么这两书一样的？
这两本书怎么一摸一样？

"为什么" doesn't always go in front of the sentence, because that sounds very textbook-style.

16. 你怎么切成西红柿？
No idea, sorry. 

17. 为什么我的饭是单的可是我的妈妈饭是非常好吃？
 为什么我的煮的饭是淡的，我的妈妈煮的饭却是非常的好吃？

单 means single and 淡 means blend. 可是 means but, and 却 adds more emphasis on the second part of the sentence, and sounds more like a "yet". "Why does the rice I cook taste blend, yet the rice my mum cooks is very delicious?"

18. 你最后教师的以后做什么？
No idea, sorry. 

19. 为什么你放掉的雨伞？
No idea, sorry. 

20. 空调是在什么毒我非常冷？
毒 is poison and 度 is degree.

空调是调到几度？我非常的冷

Are these sentence correct grammatically?