__________ the employees’ working efficiency, the supervisor will allow them to have a coffee break.
| A．Improving | B．To improve |
| C．Having improved | D．Improved |
The amount of money that he saved reached _________ 30000 dollars.
| A．as many as | B．as much as | C．as high as | D．as far as |
It is pretty well understood_______controls the flow of carbon dioxide in and out of the atmosphere today．
| A．that | B．when | C．what | D．which |
Mary got into acting purely _____________.
| A．accidental | B．accident | C．by accident | D．with accident |
It is no use thinking about your ________ youth.
| A．gone | B．lost | C．missed | D．losing |
---Must he come to sign this paper himself?
---Yes．He______ ．
| A．need | B．must | C．may | D．will |