Thismorningintheclass,ourteacherlosthis______atlastbecausehecouldnotstandanymore.

Whenmakingmoderncameras,peoplebeganto_______plasticsformetal.

Asateacher,youshouldnot_______thestudentsfromaskingquestionsinclass.

Theengineersinthislabspentseveralweeks_______theirplansforthenewbicycle.

Thisriverissobigthatitisimpossibletobuilda_______underitwithoutmoderntechnology.