【推荐2】________ you recognize an idiom when it is being used, it is easy to misunderstand what you read or hear.

A．Unless	B．After
C．Once	D．Since

【推荐3】When we start gazing into the night sky with a telescope, soon we’ll be astonished by the realization _________ we and our world are part of this giant system.

A．that

B．why

C．as

D．whether

【推荐1】______ it is raining hard, they are still working in the field.

A．Because	B．As soon as
C．Though	D．Unless

【推荐2】Personally, I think this is a touching book that everyone should read, _______ their age is.

A．whoever

B．however

C．whatever

D．whichever

【推荐3】（2015·安徽）         scientists have learned a lot about the universe, there is much we still don’t know.

A．Once	B．Since
C．Though	D．Unless