草酸的分子式为()
A.H2C2O2•1H2O
B.H2C4O2•2H2O
C.H2C2O4•2H2O
D.H2C2O2•2H2O
参考答案:C
单词拼写(共5小题,每小题1分,满分5分)
小题1:I would ______ (感激) it if you give me a chance.
小题2:Do not regard English learning as a _____ (负担).
小题3:I won't _____ (容忍) your behaving in this way.
小题4:It's a good habit to ______ (预习) what will be learned in class.
小题5:Helping each other can _____ (促进) our friendship.
压力容器的检查,说法错误的是()。
A、压力容器常的检验方法有直观检查、工具检查、无损探伤和耐压试验等
B、直观检查主要是用眼睛观察
C、直观检查是对容器进行进一步仪器检验的基础
D、超声波探伤主要用于检查容器内部缺陷