问题补充:
The old man is very healthy. I think he will live.
A. to be 100 years old
B. 100 years old
C. at 100 years old
D. in 100 years old
答案:
(答案→)A. to be 100 years old
B. 100 years old
C. at 100 years old
D. in 100 years old
解析:句意:这个老人非常健康。我认为他会活到100岁。动词不定式做状语表示具体的将要进行的动作,结合语境可知选A。