Dogs have a far wider hearing range than humans, _________ them able to detect sounds far above a human's hearing limit.
A. making B. made
C. having made D. to be made
A new engineer was appointed to deal with the products _________ by customers.
A. returning B. returned
C. to return D. return
_________ your strengths and weaknesses will help you achieve your dreams.
A. Known B. Know
C. Knowing D. Being known
We really appreciate our learning environment, _________ we can have direct communication.
A. whom B. which
C. where D. when
Sometimes tests are needed _________ doctors discover exactly what's wrong with your body.
A. since B. before
C. although D. if
The ability to make and use tools is one of the most basic characteristics of __________ it means to be human.
A. whether B. how
C. what D. when
