Years ago we didn't know this, but recen
题型:选择题
问题:
Years ago we didn't know this, but recent science _____ that people who don't sleep well soon get ill. [ ]
A. showed
B. has shown
C. will show
D. is showing
Years ago we didn't know this, but recent science _____ that people who don't sleep well soon get ill. [ ]
A. showed
B. has shown
C. will show
D. is showing