You'd better have your shoes _____ .[ ]
A. mending
B. to mend
C. mend
D. mended
答案:D
乙醇的结构简式为CH3CH2OH,则下列物质是乙醇的同分异构体的是
A.CH3COOH
B.CH3OCH3
C.CH3CHO
D.CH3COOCH2CH3
填隙碎石中填隙料的颗粒组成,要求塑性指数小于()
A.3
B.4
C.5
D.6