He can’t go to visit the Palace Museum because he has _____things to do

We don’t write to each other regularly，but we do keep intouch by telephoning _____.

Most Asian women try to be shaded from the sun while touring in Europe in summer, fearing that the strong sunshine may ______ the aging process of their skin.

The doctors say that good diet, exercise and fresh air, all of which _____ the health and long life.

There are many trees on _______side of the street, and _______of the trees is still growing.