______ the medicine works in human body is a question ______ not everyone can fully understand.
A.How; that B.That; which C.What; which D.How; what
The thought of going back home was all ______ kept him happy while he was working abroad.
A.which B.where C.how D.that
Last month, part of Southeast Asia was struck by floods, ______ effects people are still suffering from.
A.that B.those C.which D.whose
She was looking for her bicycle key ______ she thought she might have put it.
A.whenever B.wherever C.whichever D.whatever
You will find taxis waiting at the bus station ______ you can hire to reach your host family.
A.which B.what C.when D.how
The price of diamond rings has risen sharply, ______ the price of gold rings has gone down.
A.when B.which C.while D.otherwise
