除灰系统切换圆顶阀未开启报警条件是什么？
参考答案：切换圆顶阀“关”电磁阀失电、“开”电磁阀得电时间超过5秒，但是阀开压力开关仍未动作。
Sally likes comedies, ___________she doesn't like thrillers. [ ]
A. but
B. so
C. because
D. and
