People are advised not to smoke at home, since passive smoking is ________ topeople around them. Which is Not proper for the blank?
| A．dangerous | B．protective |
| C．hazardous | D．risky |
Generally speaking, my grandmother is nice and kind, but she _______ be very
stubborn at times.
| A．should | B．shall | C．must | D．can |
Most animals have little connection with animals of a different kind, _______ they hunt them for food.
| A．if | B．while | C．unless | D．as |
He loved his family, but seldom _______ spend much time with them.
| A．was he able to | B．he was able to |
| C．is he able to | D．he is able to |
A study shows that walking fast in your old age is a ______ that you will live a long life.
| A．sign | B．mark | C．symbol | D．signal |
— Where _______ you put my dictionary?
— I left it on your desk when you _______ to Tom.
| A．did; spoke | B．have; were speaking |
| C．had; were speaking | D．had; spoke |