This is _____ best kind of _____ pen you can get here.
| A．the, the | B．the, a |
| C．the, 不填 | D．a, the |
Children’s brains can’t develop properly_______ they lack protein
| A．when | B．since | C．because | D．unless |
This is the very toy car ________ which he came here the other day.
| A．by | B．in | C．for | D．on |
I began to fish before memory began, _______ I know I have always fished.
| A．so far | B．so as far as | C．as far as | D．so |
______ I had done it I knew I had made a mistake.
| A．Hardly | B．Directly | C．Mostly | D．Nearly |
Elbert Einstein, for ______ life had once been very hard, was successful later in science .
| A．whom | B．whose | C．which | D．his |