在设计控制电路时，应避免出现______电路。
参考答案：寄生
计算飞机可用率时，统计期限分为()几种。
A.年
B.月
C.半年
D.3个月
翻译短文并回答问题。
She isn't your little sister, isn't your elder sister, but she is your mother's daughter. Who is she?
Translate:
Answer:
