---Why are you back here?
--- Bad luck. We _ the last bus.
| A．missed | B．lost | C．took | D．reached |
Taking our own bags when _______can help protect the environment.
| A．shop | B．shopping | C．shops | D．shopped |
________is helpful to our environment.
| A．Cutting down trees | B．To protect animals |
| C．Not riding in cars | D．Recycle paper |
We ________ cross the street until the traffic lights turn green.
| A．mustn't | B．needn't | C．should | D．might |
You look too tired. Why not ________ a rest?
| A．stop having | B．to stop having | C．stop to have | D．to stop to have |
Let's ________ the TV to watch the news program.
| A．turn on | B．turn down | C．turn up | D．turn off |