Reading books ________ a bridge between our lives and the unknown world．（ ）
| A． |
built |
B． |
build |
C． |
builds |
Chinese parents always try their best ________ a good education environment for their kids．（ ）
| A． |
provide |
B． |
to provide |
C． |
providing |
"Tom， would you please take out the rubbish？"
"Just a minute， mom， I ________ a phone call．"（ ）
| A． |
make |
B． |
makes |
C． |
am making |
"Do you know ________ the school library closes， Susan？"
"Ten o'clock at night．"（ ）
| A． |
when |
B． |
why |
C． |
who |
The doctor looks tired and sleepy ________ he stayed up late to look after his patients yesterday．（ ）
| A． |
because |
B． |
if |
C． |
unless |