19..Someone is at the door, who is_________?
20.
| A．this | B．that | C．it | D．He |
“I was touched by the children here who called me ‘Grandpa Wen’ because that’s _______the Chinese children call me at home,” said former premier Wen Jiabao in India．
| A．how | B．what | C．why | D．when |
—Is there any possible way to help them get rid of such a bad habit?
—To tell the truth, it’s very hard. But we ________ on this problem, trying to improve the situation .
| A．worked | B．had worked | C．are working | D．had been working |
We give dogs time, space and love we can spare, and ________, dogs give us their all.
| A．in all | B．in fact | C．in short | D．in return |
It is a long time ________ they separated, but it won’t be long ________ they meet again.
| A．since, before | B．after, when | C．since, when | D．after, before |
Only when I checked the paper once more _________ there was a mistake.
| A．I realized | B．did I realize | C．I had realized | D．had I realized |