After ____ seemed like hours he came out with a bitter smile.
| A．which | B．it | C．what | D．that |
Having a walk after supper is certainly good for the old people, but it remains ______ whether they will enjoy it.
| A．to see | B．to be seen | C．seeing | D．seen |
If better use is _______ your spare time, you will have a more brilliant future.
| A．made of | B．spent | C．used for | D．taken |
The fire made _____ difficult to rescue the people trapped under the ruins in the earthquake.
| A．/ | B．this | C．that | D．it |
The world will be different, and we will have to be prepared to ________ the change.
| A．adapt to | B．adopt to | C．apply to | D．devote to |
You were silly __________ your car, otherwise it wouldn’t have been stolen.
| A．not locking | B．to not lock | C．not having locked | D．not to lock |