-----HowoftendoIneedtowaterthehorses? -----They
来源：语文精选馆 1.92W
问题详情：
-----How often do I need to water the horses?
-----They ________ water every day, or they will be thirsty.
A. must give B. mustn’t give
C. must be given D. mustn’t be given
【回答】
C
知识点：情态动词
题型：选择题
