. Teachers recommend parents ___ their children under 12 to ride bicycles to school for safety.
| A．not allow | B．do not allow | C．couldn’t allow | D．mustn’t allow |
Not knowing how to grow crops，the primitive people had no ______ but to gather the fruit and hunt animals for food.
| A．conception | B．command | C．virtue | D．alternative |
—Did you meet with the famous star yesterday?
—______ I had come a little earlier!
| A．If only | B．Only if | C．But for | D．For fear |
A lot of children never fully ______ their mothers until it is too late.
| A．urge | B．appreciate | C．accuse | D．motivate |
______ I admit that there are problems, I don't agree that they cannot be solved.
| A．As | B．If | C．While | D．When |
Small _____ it is, the pen is a most useful tool.
| A．because | B．so | C．if | D．as |