我国三个主要半岛所属省区分别是( )
A:山东、江苏、浙江
B:广东、广西、海南
C:山东、上海、广东
D:山东、辽宁、广东
— Jack has made a decision.
— But I suggest that he should think it over so that he won't regret it later on.
人正常体液pH都在相对稳定的范围内,否则人会生病。人体体液中酸性最强的是( )
如图所示,a∥b,∠1=158°,∠2=42°,∠4=50°.那么∠3=( )