—When are you leaving for Guangdong?
—My plane at six．
| A．took off | B．would take off | C．will take off | D．takes off |
Exactly______ the potato was introduced into Europe is uncertain, but it was probably around 1565.
| A．whether | B．why | C．when | D．how |
Today there are more airplanesmore people than ever before in the skies.
| A． | carry | B． | carrying | C． | carried | D． | to be carrying |
Unless some extra money________, the theatre will be close.
| A．was found | B．finds | C．is found | D．found |
—I’m sorry for breaking the cup.
—Oh, _________一 I’ve got plenty.
| A．forget it | B．my pleasure | C．help yourself | D．pardon me |
—I can't remember those grammar rules!
—__________. Practice more.
| A．You're not alone | B．It's hard to say |
| C．I'm afraid not | D．It's up to you |