Trees take harmful gas from the air, and ______ oxygen (氧气) into the air.
A: let out
B: set off
C: give up
A: let out
B: set off
C: give up
举一反三
- Please open the window, and let the fresh air _______. A: in B: out C: from D: off
- Please these parcels by air at once. A: look at B: take up C: live in D: send off
- Many power stations have been modernized to( )less pollution. A: set off B: give out C: set out D: give off
- Buses have routes. They ________ and ________ people at different places on the routes. A: take on, get off B: pick up, drop off C: take up; take off D: pick out; drop out
- Do you mind ________? A: to turn up the air conditioner B: turn up the air conditioner C: turning up the air conditioner D: to turning up the air conditioner