True friendship is like sound health, _____ value is seldom known until it is lost.
| A．whose | B．of which | C．as | D．which |
—— Was that the new comer who walked by?
—— ＿＿＿＿＿.
| A．It must be that | B．It must have been | C．He must be | D．This must have been |
＿＿＿＿being March 12th, they planted trees on the hill.
| A．That | B．It is | C．It | D．This |
—— Have you ever seen a whale alive?
—— Yes, I’ve seen ＿＿＿.
| A．that | B．it | C．such | D．one |
＿＿＿＿four years since I joined the army.
| A．There was | B．There is | C．It was | D．It is |
We had to be patient because it＿＿＿some time ＿＿＿we got the full results.
| A．has been ； since | B．had been ； until |
| C．was； after | D．would be ； before |