I often go to work________．
| A．ride my bike |
| B．by bike |
| C．by a bike |
| D．on bike |
is very difficult for them babies .
| A．It , have | B． That, to have |
| C．That , make | D．It, to have |
This canaccident from happening .
| A．start | B．prevent | C．learn | D．help |
Mr. Wang often tells usof the window in class .
| A．to look out |
| B．don’t to look out |
| C．not look out |
| D．not to look out |
If people change the wetlands to make for farms , the birds will not have enough to live .
| A．space , rooms | B． spaces , room |
| C．rooms , space | D．room , space |
Zhalong Nature Reserve is an importantarea of the rare crowned-cranes .
| A．alive | B．lively | C．living | D．lovely |