$\textit{@chanhbakaa}$

1,

$\rightarrow$ C1: If you don't study your lessons carefully, you will fail the exam: 

$\rightarrow$ C2: If you study your lessons carefully, you won't fail the exam.

2, 

$\rightarrow$ C1: If you try your best, you will be a good student.

$\rightarrow$ C2: If you don't try your best, you won't be a good student.

3, 

$\rightarrow$ C1: If they come right now, they won't be late for the bus.

$\rightarrow$ C2: If they don't come right now, they will be late for the bus.
4, 

$\rightarrow$ C1: If Lan studies hard, she won't get poor result.

$\rightarrow$ C2: If Lan doesn't studies hard, she will get poor result.

$\Rightarrow$ Giải thích:
- Sử dụng câu điều kiện loại 1.