(2013·福建，22)________ basic first－aid techniques will help you respond quickly to emergencies.
A．Known B．Having known
C．Knowing D．Being known
(2013·北京，21)Volunteering gives you a chance ________ lives, including your own.
A．change B．changing C．changed D．to change
________ several times，but he still doesn't know how to do it correctly.
A．Although I've taught him
B．I've taught him
C．Having been taught
D．Having taught
Information technology is taught in most schools，________ we have entered the information era.
A．so B．while
C．for D．still
It's really very dangerous.One more step，________ the baby will fall into the well.
A．or B．so C．but D．and
There is still much to discuss；________，we shall return to this topic at the next meeting.
A．yet B．therefore
C．otherwise D．however
