直线段两股钢轨应水平，误差不大于（）毫米。
A、3
B、4
C、2
D、5
参考答案：B
填入一个适当的词，补全对话。
—Good morning!
—1______ 2______!
— What's your 3______?
—My name is Jack Smith.
—What's your 4______ name, please?
—It's Smith
—What's your 5______ 6______?
—It's 8931645
—OK, Thank you very much. Goodbye!
—Bye!
起重机司机室的净空高度都不应小于2m。
