— Oh, it's my sweater. Please ______ for me.
A:pick up it
B:pick it up
C:pick it out
____
如图为氢原子的能级图,现有大量的氢原子处于n=4的激发态,当它们自发地跃迁到较低能级时( )
下列句子中,划线的词语使用不正确的一项是( )