Mary suggested that the problem worth paying attention __________at the meeting. [ ]

As we know it’s difficult to live in a foreign country．—________if you can’t understand the language there．

When can I see you, Mr Black? Three o’clock this afternoon?— Oh, noI ________ a meeting then

During the rainy days, I prefer to stay at home ___________ go out.

Sometimes parents find ______ hard to communicate with their children.