—What’s Jack up to in the shoe shop? He’s there for ages.—It’s ______ that he hasn’t decided which pair to buy.
When he ______ the door, he found his keys were nowhere.
—Putting on a happy face not only helps us make friends but also makes us feel better. —______.
We can relax ourselves by taking part in school activities after long hours’ study; _______, we can learn a great deal from other students.
Some buildings in the past ______ down and new ones are being built there.
The movie, ______ in a family of three generations in Shanghai in the 1940s, enjoyed a great success.