It is difficult for us to learn a lesson in life_____we’ve actually had that lesson.
| A．until | B．after | C．since | D．when |
I'll go to the library as soon as I finish what I .
| A．was doing | B．am doing | C．have done | D．had been doing |
Tomin the library every night over the last three months.
| A．works | B．worked |
| C．have been working | D．had been working |
—Bob has gone to California.
—Oh, can you tell me when he ?
| A．has left | B．left | C．is leaving | D．would leave |
You ____ television. Why not do something more active?
| A． always watch | B． are always watching |
| C． have always watched | D． have always been watching |
Turn on the television or open a magazine and you ________ advertisements showing happy families.
| A．will often see | B．often see |
| C．are often seeing | D．have often seen |