They have been to Beijing for two days.变否定句,一般疑问句,特殊疑问句.要正确率高的,

问题描述:

They have been to Beijing for two days.变否定句,一般疑问句,特殊疑问句.要正确率高的,

They haven't been to Beijing yetHave they been to Beijing for two days?How long have they been to Beijing?