问题补充:
Old Henry take his dog for a walk after supper. But these days he is too weak to do that.
A. has to
B. is able to
C. used to
D. got used to
答案:
A. has to
B. is able to
(答案→)C. used to
D. got used to
解析:have to 不得不 be able to能够做某事get used to sth习惯于某事 ,句意:亨利老人过去常常晚饭后去遛狗。但现在他太虚弱了而不能这么做了。故选C.