Danny _____ to send nine postcards to his mother. [ ]
A. want
B. wants
C. wanting
答案:B
下列定义变量的语句中错误的是______。(A) int _int;(B) double int_;(C) char for;(D) float US$
水中甲醛的测定多采用乙酰丙酮光度法。简述惭酰丙酮光度法的优点。