We____be careful when we cross the street.
举一反三
- Be careful when you ________ the street. A: are crossing B: is crossing C: crossing D: is cross
- 中国大学MOOC: ________ my hand while we cross this street.
- We should be really careful when we use common knowledge.
- We can say "we’ll cross that bridge when we come to it" if someone asks about ______.
- We started the attack when the enemy (cross) ______ the river.