____ you know your potential（潜力）, you have to rely on many other people to get to where you are.
| A．While | B．Since | C．If | D．Where |
She was afraid __________ the dog in case it became dangerous.
| A．of exciting | B．to excite |
| C．that she excited | D．to be exciting |
We're leaving at six o'clock ,and hope_________ most of the journey by lunch
time.
| A．to do | B．to have done | C．to make | D．to have made |
I__________ you somewhere before, but your name has escaped me_________.
| A．must see;for a moment | B．must have seen; for a moment |
| C．must see;for the moment | D．must have seen; for the moment |
What worried the child most was _________ to visit his mother in the
hospital.
| A．his not allowing | B．his not being allowed |
| C．his being not allowed | D．having not been allowed |
Michael __________ here to see you and he____________ a note on your desk.
| A．has come; had left | B．has been; has left |
| C．has come; left | D．has been; left |