呼吸阀发生故障或损坏时，要及时进行（），不得随意堵死或取消。
参考答案：修理和更换
皂化值是衡量乳化液杂油含量的重要指标。
They like ______ after school.
A．play the basketball
B．play basketball
C．to play the basketball
D．to play basketball
