It is ________ he often fails in exams ________ makes his parents worried about him.

A．what；that.

B．that；what.

C．that；that.

D．because；that.

下列说法错误的是( )。

A．家用冰箱不宜存放汽油、乙醇等易燃性液体
B．使用于粉灭火器灭火时，应对准火焰的底部喷射
C．火灾现场中首先对人体造成危害的一般是烟雾和毒气
D．发现室内燃气泄漏，应打开门窗，关闭气源和大功率家用电器