问题
选择题
Hawking became world-famous in _______.
his thirties in the 1970’s
the thirties in his 1970
his 30s in 1970’s
the thirties during the 1970
答案
答案：A
选A。in one’s thirties 在某人三十多岁时，in/during the 1970s意思是“在二十世纪七十年代”。