When you get involved in sports, a lot of racial____are broken down because players developed friendship quickly. 

 While working outdoors, Linda was ________ by the heat and fell to the ground, unconscious.

To save class time，our teacher has ________ students do half the exercise in class and complete the other half for our homework.

________ doing his experiment, he forgot to pick up his wife from the station. 

It’s hard to tell real Jingdezhen vases, and it’s a little more difficult for the untrained shopper to______.