My most devoted friend, Professor Yang, _______ often go hiking when he lived in the mountain that was covered with forest.

It is believed that the test system,__________ the teachers, ______to blame for the heavy burdenof middle school students nowadays[ ]

We can ________ with each other by e-mail with the help of the Internet nowadays.

in the woods, the cottage was a good shelterfrom the enemies.

Each of us should take action hunters catching bears for their fur. Otherwise, there will be no bears left in the world.