Didn’t ever occur to you what the source of this saying I just quoted is?
| A．this | B．it | C．that | D．one |
The police________ already_______ his house but haven’t found any evidence against him.
| A．has; searched | B．have; searched | C．has; searched for | D．have; searched for |
We should consider the students’ request________ the school library should provide more books on popular science.
| A．that | B．when | C．which | D．where |
He was heard________ three songs in the next room.
| A．sing | B．to sing | C．singing | D．sung |
-Young man, come off the grass; we forbid________ on the grass here.
-Sorry, I didn’t notice it.
| A．to stepping | B．stepping | C．why | D．which |
Christina wasn’t saying anything, but the professor smiled at her _______she had done something very clever.
| A．as if | B．now that | C．while | D．though |