The last time we had great fun was _____ we were visiting the Water Park.
20.—Would you please tell Linda to come to my office? —Yes.___________.
19.We’d better set off now, or it will be dark__________we know it.
18.Mary said she didn’t care anything about John, but her red face________.
17.—Is there any better way to help my son get rid of the habit of playing computer games? —To tell you the truth, it’s very hard. But we_______on this problem to improve the situation.
16.—Where is Lily, Lucy? I cannot find her anywhere. —She_________have been off long. I saw her clean the window just now.