Look out!That milk ____(boil) over.

问题描述:

Look out!That milk ____(boil) over.

Look out!That milk boil over.

is boiling。look out为现在进行时的标志

is boiling 此处一方面是为了引起人的注意;另一方面,与前文的Look out呼应,表示一种即将要沸的意思,是用进行时态表将来

is boiling
应为引起别人的注意