除去下列物质中所含少量杂质(括号内),所选用的试剂和分离方法能达到实验目的的是
Charles was alone at home, with_______ looking after him.
It is often ______ that human beings are naturally equipped to speak.
I can’t leave. She told me that I ______ stay here until she comes back.
—— Do you mind my opening the window? It’s a bit hot in here. —— ______ , as a matter of fact
It’s high time you had your hair cut ; it’s getting _______ .