问题
选择题
Tom ______ swimming for 3 hours, and his son ______ an hour ago. [ ]
A. has started; has started
B. have started; has started
C. started; started
D. has been; started
答案
答案:D
Tom ______ swimming for 3 hours, and his son ______ an hour ago. [ ]
A. has started; has started
B. have started; has started
C. started; started
D. has been; started
答案:D