proficiency
n[U]
~ (in sth/doing sth)being proficient (in sth) 精通; 熟练
a test of proficiency (in English) (英语)水平测试
show proficiency in operating a switchboard 操作配电板十分熟练.
And I can't find her passport anywhere. So she must have taken that too.
而且我在哪都找不到她的护照,所以她一定也带去了。
The question was, which one?
问题是,哪一种气体导致火灾呢?
So, celebrate your success, and invite your parents to celebrate with you, however hard it may be for them. If you continue to be excited about your future, you may come to educate your parents in the same way.