—Those scientists invented a robot to ca
题型:选择题
问题:
—Those scientists invented a robot to care for kids!
—It's not surprising. They ________ wonders all the time.[ ]
A. worked
B. were working
C. work
D. have been working
—Those scientists invented a robot to care for kids!
—It's not surprising. They ________ wonders all the time.[ ]
A. worked
B. were working
C. work
D. have been working