They couldn't speak Chinese 2 years ago ,and now they still( ).(用can,could,may,must回答)

问题描述:

They couldn't speak Chinese 2 years ago ,and now they still( ).(用can,could,may,must回答)

语法题,前面有2 years ago,还有NOW,明显考的是时态,所以用can,应该是高中以前的题目.