There are many words in the English language.You will never_

There are many words in the English language.You will never___the meaning of every word in English.When you read,you will often find many___you do not know.You will not have enough time to___reading and try to find every new word in a dictionare.
Sometimes you can___a new word because you know some of the parts of the new word.For example,if a word ends___the letters"er”,that word___be the name of a___or a thing that does a certain action.A writer is a person who writes.___it is not___to know the part of a new word to understand it,___it will help you many times.
( )1.A.know B.learn C.find D.look up
( )2.A.books B.letters C.stories D.words
( )3.A.stop B.enjoy C.keep D.start
( )4.A.find B.get C.study D.guess
( )5.A.in B.off C.up D.with
( )6.A.can B.might C.should D.must
( )7.A.friend B.boy C.person D.girl
( )8.A.Then B.Now C.Yet D.Sometimes
( )9.A.helpful B.useful C.enough D.good
( )10.A.but B.and C.so D.for