---Does Cindy go to school by _____ bus?---No, she doesn’t. She takes ______ underground.
You should _______ in the dictionary when you meet a new word.
It’s a good idea _____ a pen friend to practise English.
How many ______ medicine are used for the children of six years old?
Eating fruit and vegetables can help you ______ more vitamins.
Here ______ in the classroom.