1. what if

假使…将会怎么样

eg. What if I have no debts?

如果我没债务怎么办？

eg. One of each? What if you have triplets?

假如生了三胞胎会怎么样？

2. sit up

熬夜；端坐

eg. Her head spins dizzily as soon as she sits up.

她一坐起来，就感到天旋地转。

eg. The patient was but poorly able to sit up.

病人仅能勉强坐起来。

3. on fire

着火；起火

eg. Yes, that's the band and, yes, they are on fire.

是的，那就是他们整个乐队，而且他们是着火了。

eg. It looks as if it is on fire.The canyon fills most of the picture.

它看起来好像着火了，峡谷填充了这张图片的大部分面积。