.To improve your health, you can _________ 25— 30 minutes three or four times a week to do simple things such as walking ,cycling or running .

 It’s reported that the fire that ______ at two o’clock last night caused a lot of damage.

 The colors on the national flags can be ______ differently in different culture, but they have one thing in common, that is, ______of the colours was carefully chosen.

 You should _______ any opportunities you have to practice English.

A good idea __________ to me, and I quickly picked up the phone to tell Jack about it.