It’s high time that they _____ some seriouswork right now.

(2013·高考北京卷)Don’t turn off the computer before closing all programs，________you could have problems

____ without friends _____ the most difficult challenge for Chuck while living on the island. [ ]

So far the number of deaths caused by the earthquake in Chile has _________750.

Take care during the holidays! Drinking too much can ____ heart disease and cause high blood pressure.