in the past l was very lazy but now l (change)填啥?

问题描述:

in the past l was very lazy but now l (change)填啥?
our city (change) a lot.

have changed

has changed

为什么?第一句状语是now, 指“现在已经变了”, 用现在完成时第二句没有状语和上下文限制, 主语是单数, 用现在完成时没错。 只是要注意别用have