根据《液压爬升模板工程技术规程》,模板系统中,单块大模板至少应配置()套架体或提升架。
A.5
B.4
C.3
D.2
参考答案:D
焊接碳钢时,通常都不使用熔剂,这是由于气焊火焰中所含的()起还原作用的缘故。
A、CC;CO;H
B、C;H;O
C、C;CC;H
D、C;H;CH
A recent study by the Center for Economic Policy Research says that, in order to ease imbalances, the European Union needs to make changes while the United States has to spend more and save less.