金属在长期高温下金相组织结构发生的变化有以下（）几种。A、石墨化；B、合金元素在固溶

Did you _____________ your grandparents? [ ]

A. visit

B. visits

C. visited

机车段修对油水管路系统有哪些检修要求？

场检测预备加压正确的有（）

A、施加三个压差脉冲

B、压力差为500PA

C、压力差为150PA

D、加压速度约为100PA

When inspecting a tank barge to see that it has all the required fire extinguishers and other safety items aboard，which of the following is the best source for determining what is required?（）

A.The supervisor in charge of the dock to which the barge is tied up

B.Part 38 of the Rules and Regulations for Tankers

C.The Certificate of Inspection of the barge

D.The local fire marshal

“沉舟侧畔千帆过，病树前头万木春”这句唐诗蕴涵的哲学道理是（）

A.矛盾是事物发展的动力

B.事物是本质和现象的统一

C.新事物代替旧事物是事物发展的总趋势

D.事物的发展是量变和质变的统一