Paper is ________ useful invention.It was invented around 2,000 years ago by Cai Lun.( )
A.aB.anC./D.the
— I'm afraid that we can't the math problem the teacher helps us.
— That's true.It's too difficult.
A.work on;ifB.work on;unless
C.work out;ifD.work out;unless
— Which country has a population,China or Canada?
— China.Canada is a lot crowded than China.
A.bigger;lessB.bigger;more
C.smaller;lessD.smaller;more
If you want to be a doctor like Zhong Nanshan,hard work is the key to .
A.treasureB.beautyC.successD.health
My mother will be years old next week.I'm planning to buy a gift for her birthday.
A.fourty;fourtiethB.forty;fortieth
C.fourty;fortiethD.forty;fourtieth
The two books are about English.You can choose of them to read.
A.all;bothB.all;either
C.both;eitherD.both;neither