穿梭油轮卸软管应检查（）型垫圈是否良好，必要时更换新的垫圈。
参考答案：0
农村低压电力客户服务的用电报装是指什么？
Your parents are both teachers, ______ they? [ ]
A. are
B. aren't
C. do
D. don't
