Water，which seems so simple and common，is ________ makes life possible.
| A．what | B．that |
| C．which | D．how |
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 |
The detective, ________ to read a newspaper, glanced at the man ________ next to a woman.
| A．pretending; seat | B．pretending; seated | C．pretended; seat | D．pretended; seated |