在开启注胶机前，必须保证（）处于关闭状态。
A、安全防护罩
B、手动开关
C、探测器
D、安全阀
参考答案：A
What ______ will it ______ whether you are a boy or a girl? As long as you set your mind to it, nothing can be difficult.
A．differences, tell
B．sense, make
C．difference, make
D．use, make
发送车流秩序的基本要求有哪些？
