certain that his invention will lead to the development of production.
| A．That's | B．This is | C．It's | D．What's |
These shoes look very good. I wonder __________.
| A．how much cost they are | B．how much do theycost | C．how much they cost | D．how much are they cost |
—What did your parents think about your decision?—They always let me do __________ I think I should.
| A．when | B．that | C．how | D．what |
—It’s thirty years since we last met.—But I still remember the story, believe it or not, __________ we got lost on a rainy night.
| A．which | B．that | C．what | D．when |
— Could you do me a favour?— It depends on __________ it is.
| A．which | B．whichever | C．what | D．whatever |
We haven’t settled the question of __________ it is necessary for him to study abroad.
| A．if | B．where | C．whether | D．that |