环氧树脂多用于修补哪种混凝土缺陷()。
A.麻面
B.露筋
C.裂缝
D.蜂窝
参考答案:C
—Tom has never visited the Great Hall of the People, _____?
—He went there last month.
A.hasn’t he; No, he hasn’t
B.has Tom; Yes, he has
C.hasn’t Tom; No, he hasn’t
D.has he; Yes, he has
黄芩原植物为()。