The chemistry teacher asked the students ________ more attention _________the lab clean.
| A．to pay ,to keep | B．to paying ,to keeping |
| C．to pay , to keeping | D．paying ,keeping |
I ________ when the UFO landed.
| A．am watching TV | B．was watching TV |
| C．have watched TV | D．watched TV |
I have two brothers. One is a teacher, _________ is a doctor.
| A．another | B．other | C．others | D．the other |
I _________ $300 for the bike.
| A．took | B．spent | C．cost | D．paid |
There are many _______ playing on the playground.
| A．child | B．children | C．man teachers | D．sheeps |
A horse is _______ useful animal.
| A．a | B．an | C．the | D．/ |