A:that
B:when
C:which
D:where
在电风扇、电熨斗、电磁起重机、动圈式扬声器、动圈式话筒和发电机这些装置中,利用电磁感应原理工作的有____ 、____
The upset mother thought to herself, “If only I ______ what's going on in my little boy's head right now.”
如图是我省某气象站测得的某月18~21日气温和气压变化图.读图回答下题.