--Excuse me, teacher, can I ask you something about the last class? I didn’t quite understand it.--Sure! Please feel _________to ask me anything!
– May I take the magazine out of the reading room? -- No, you can’t. You read it here. It’s the rule.
Everyone went to the zoo last Sunday ______Jim.
____ will he be back? In a week.
If you miss so many lessons, you must fall behind ____ classmates.
I found _____ very difficult to learn maths well.