Pine trees are usually believed to _______ cold weather.
A、guardD
暂无解析
Severalloudspeakersare_______fromtheceilingandwecanhearthespeakerveryclearly.
Thismorningintheclass,ourteacherlosthis______atlastbecausehecouldnotstandanymore.
Theengineersinthislabspentseveralweeks_______theirplansforthenewbicycle.
Whenmakingmoderncameras,peoplebeganto_______plasticsformetal.
Thisriverissobigthatitisimpossibletobuilda_______underitwithoutmoderntechnology.
