咽喉区通过能力是指（）。
参考答案：咽喉区通过能力是车站某咽喉区各方向接、发车进路咽喉道岔组通过能力之和
People are advised not to drive after drinking, and _____ seems to help a lot. [ ]
A . it
B. which
C. they
D. one
水准测量每次读数前一定要使（）居中。
A.指标气泡
B.长气泡
C.园气泡
D.对中器
