求情态动词can、could、must、have to和should的练习题共20道题（全选择题也行,

1.I’m sorry.I ___ go now.My father told me on the phone that my mother was ill.(05厦门）A.can B.may C.have to D.think2.“Where’s my umbrella?” “It’s fine today.You ___ take an umbrella with you....