1 . The students were divided into pairs, ________ Lily wasn’t happy with.

A．which

B．where

C．who

D．what

2 . My computer crashed yesterday. Without it, I can’t go on with my online lessons. (用定语从句合并)
My computer, ______ I can’t go on with my online lessons, crashed yesterday.

3 . Daylight saving time begins at 2: 00 a. m. local time on the second Sunday in March, ________clocks spring forward an hour, typically ________observers to lose an hour of sleep.

A．which, caused

B．when, causing

C．which, causing

D．when, caused

4 . He had a deep voice,________ set him apart from others in our small town, and he was strong and powerful.（用适当的词填空）