_______ basic first-aid techniques will help you respond quickly to emergencies.
| A．Known | B．Having known |
| C．Knowing | D．Being known |
Stressful environments lead to unhealthy behaviors such as poor eating habits, which _____ increase the risk of heart disease.
| A．in turn | B．in return | C．by chance | D．by turns |
Teenagerstheir health because they play computer games too much.
| A．have damaged | B．are damaging | C．damaged | D．will damage |
——I am afraid I can’t return the book to you before Friday.
——.
| A．Don’t be afraid | B．Be careful | C．Not at all | D．Take your time |
All people,they are old or young, rich or poor, have been trying their best to help those in need since the disaster.
| A． | even if | B． | whether | C． | no matter | D． | however |
The artist was born poor,poor he remained all his life.
| A．and | B．or | C．but | D．so |