When I walked past her room， she_______ an English song.
A. singing B. was singing C. sang D. sing
- He________ if he is free.
A. will come B. comes C. come D. Came
—What was Tom doing _______ it was raining?
—He was doing his homework in the bedroom.
A. since B. while C. for D. who
Some scientists believe that there more robots in the future.
A will have B. will has
C. will be D. Are
They ________ TV at ten o’clock last night.
A. was watching B. were watching
C. watched D. Watches
It will be difficult ________ a robot_________ same things as a person，
A. of， do B. for， to do
C. for， doing D. for， do
