For instance, in the first one, when person A says he/she could not finish his/her homework, why would person B assume there was something wrong with his/her computer? It’s as if person A should have said, “I could not finish my homework because my computer is acting up.”

In the second one, it would make more sense if person A said, “I’d like to get married, but Susan is the woman interested in me and I don’t think she’s right for me.”

The third: “When shall we meet? How about Wednesday?”

The fourth: “I want to make better grades without spending more time studying.”

Again, these aren’t grammar corrections; they just make the conversation flow better. These suggestions are in addition to the grammar corrections given by the first answerer.

Keep up the good work!

A : I could not finish my homework on the laptop.

B : What’s wrong with your computer?

A : I don’t know. It won’t boot up.

B : You’d better call the support center right away.

A : I’d like to get married to Susan, but–

B: But what? What’s wrong with Susan? She is a wonderful person. And pretty.

A: She is a little proud.

B: Is she really proud, or are you really just too shy to ask her?

(With whom would you have had that conversation? Who would you gossip with about a woman before you decided to marry her??)

A : When shall we meet?

B : What’s wrong with tomorrow?

A : Tomorrow would be fine.

B : Please don’t forget to an umbrella. It’s supposed to rain tomorrow.

A : I want to make better grades.

B: What’s wrong with studying harder?

A : I am afraid I am too busy these days.

B: Come on! You will fail the next exam.

I made minimal changes. Let me know if you need to know why I made the changes I chose to make.

In the second dialog, we are patient with a small thing, not to it. What’s wrong with tomorrow is question. We use the infinitive when speaking of the very near future. Please don’t forget to bring an umbrella would be correct, and the following sentence should have a subject and verb, as in It’s supposed to rain tomorrow.

I am afraid I am too busy these days (to study harder). And the last sentence is a little harsh, it’s a prediction of failure. It would just be more polite to make it conditional by saying “You might fail your next exam.”