Hi Hongju. There are some different usages for the modal verb "Should". The first usage is "Obligation". I should be there by 5 PM. (I have an obligation to be at a place by 5, otherwise there will be some consequences.) 2.Advice" You should try harder. 3.Recommendation. When you go to NYC, you should visit the wall street. 4.Expectation. By now, the class should be over. Pay more attention to number 4. It talks about expectations. Now let's look at your sentences. 1. It's strange that he should be late. He's usually on time. The person is usually on time, but he is gonna be late and we don't expect it. 2. I was surprised that he should say such a thing. I didn't expect him to say such a thing so I was surprised (As Michael mentioned this )

All correct. You are doing good. Keep this amazing job up. 👍🏻👍🏻

When you say "What are you doing?" (Present continuous tense), The answer needs to be the same tense, so I say " I am / I'm making a cake" When you say " What do you do?" I say " I make a cake" Do you travel? Yes, I do. I travel to many countries.

You didn't want to say anything until you were sure. So Don't say "Until it was sure". The other 2 ones are right. 👍🏿

There are many phrases. You can say: It’s nice to meet you. It’s a pleasure to meet you. It's great connecting with you. Pleased to meet you. Lovely to meet you. How do you do? (Formal. Especially in Britain) Delighted to make your acquaintance. (Very formal)

Change and alter can have exactly the same meaning, but in general, to alter something is to make a small but significant change. Change on the other hand can mean make a small change in something, or a very large change in something, or it can mean replacing one thing entirely with something else. So change covers a larger range of meanings than alter.

As Xavier said, the 2nd one needs to be "lots of ..." which looks like you made a mistyping. But if you don't mind, I'd like to challenge you. Can you explain what is the difference between "Boring" and "Bored" ;) let me know if you need help.