题目

When people take a vacation, can they always enjoy it?The fact is that some people who travel for pleasure get no pleasure from it at all. Others, who travel because they must travel, have a lot of fun doing it. What makes one trip more enjoyable than another?Any trip can be enjoyable if you plan it well. Every minute that you spend in planning your trip may save your ten minutes of trouble during your trip. It may also add an hour of pleasure!Many places of interest and cities around the world are popular during some months of the year and less popular during other months. Find out if the plaYou didn't hear me until now? No, I must ________ soundly when you came in. [　　] A．have sleptB．be sleeping C．have been sleepingD．sleep