. Going out for tea with friends increasingly popular during the past twenty years.
| A．becomes | B．became | C．has become | D．had become |
Key: C
. ____ it will do us harm or good remains to be seen.
| A．If | B．Whether | C．That | D．Where |
. The river, ____ are covered with trees, is very long.
| A．which banks | B．of which banks |
| C．whose the banks | D．the banks of which |
He is rather difficult to make friends with, but his friendship, ____, is more true than any other.
| A．once gained | B．when to gain |
| C．after is gained | D．while gaining |
1. — Have you known each other for long?
— Not very long, ____ we started to work in the company.
| A．after | B．before | C．when | D． since |
__________ some medals came to live in the sea is not known.
| A．Which | B．Since | C．Although | D．How |