In the office an electrical engineer is
题型:选择题
问题:
In the office an electrical engineer is looking through the instructions to know ________ the heat system works before the repair work.
A.whether
B.why
C.how
D.that
In the office an electrical engineer is looking through the instructions to know ________ the heat system works before the repair work.
A.whether
B.why
C.how
D.that