题干
Safety in school has be
en of great concern because of frequent reports about accidents _______ students got injured or killed while in school．
en of great concern because of frequent reports about accidents _______ students got injured or killed while in school．
A：in which
B：whe
C：that
D：for which
答案(点此获取答案解析）
A
为直流电源，
为浸透饱和氯化钠溶液和酚酞试液的滤纸，
为电镀槽．接通电路后发现
后，使c、d两点短路．
