_____ these experiments were successfully completed would we think of
going into humans.
| A．If only | B．So that | C．Only if | D．Even if |
I cannot thank you ________ much. I might never have been admitted to such a famous university but for you.
| A．quite | B．that |
| C．too | D．very |
We'd better grow the plant in a ________ plastic box so that the children can see the roots growing.
| A．safe | B．square |
| C．transparent | D．thick |
—Oh, I've just locked my keys in my office again.
—You're always so careless, but ________ let's see what we can do about it.
| A．otherwise | B．therefore |
| C．anyway | D．besides |
—Language learning is much ________ for children.
—Yeah, I quite agree. Their minds are more flexible.
| A．easier | B．easy |
| C．the easiest | D．the easier |
With the help of the high technology, this year the factory has produced ________ it did last year.
| A．twice as many as | B．twice as many cars as |
| C．twice as many as cars | D．twice cars as many as |