《中国药典》中庆大霉素C组分检查方法是()
A.气相色谱法
B.正相高效液相色谱法
C.比色法
D.反相高效液相色谱法
E.紫外分光光度法
参考答案:D
They gave me so much help, without ____ I couldn't have succeeded last year.
A.them
B.which
C.it
D.that
A,B,C是相邻的3种元素,A,B同周期,B,C同主族,且3种元素的质子数总和为30,写出这3种元素的名称_________________________