_______ he was 12, Einstein had learned advanced mathematics by himself.
| A．As soon as | B．At the time | C．By the time | D．During the time |
A cook will be immediately fired if he is found ________ in the kitchen.
| A．smoke | B．smoking |
| C．to smoke | D．smoked |
He found his son________by letters and papers and________very worried.
| A．surrounding；looked |
| B．surrounded；looked |
| C．surrounding；looking |
| D．surrounded；looking |
________you may have，you should gather your courage to face the challenge.
| A．However a serious problem |
| B．What a serious problem |
| C．However serious a problem |
| D．What serious a problem |
I used to love that film________I was a child，but I don’t feel it that way any more.
| A．once | B．when |
| C．since | D．although |
There were some chairs left over________everyone had sat down.
| A．when | B．until |
| C．that | D．where |