某原子的核内质子数为18,中子数比电子数多4。则该原子核内所含粒子总数(质子数 + 中子数)为 [ ]
A.18
B.22
C.40
D.58
答案:C
He promised to pick me up at the school gate. However, he yet.
A、hasn’t arrive
B、didn’t arrive
C、doesn’t arrive
通常,销售利润率较高的行业,其资产周转率较低;资产周转率较高的行业,其销售利润率较低。 ( )