While____the dog,you should take care not to____.Otherwise,it may be dangerous to strangers.

The foreiger knows little about ______ is called "Hope Project" in China.

Ms. Claire is a strict but kind teacher, _____ who, usually, _____ her students.

The revolutionary system of farming, said the Israeli government spokesman, was one_____ he believed could change the face of modern agriculture.

The man put out the cigarette when _______ that smoking was not allowed on the train.