1.The Yellow River is the second ______ river in our country.
A.the longest B.longest C.longer D.long
2.My uncle likes to watch the goldfish ____ around in the tank.
A.swim B.swims C.to swim D.swam
3.I don't think _____necessary to tell you about it
A.this B.that C.him D.it
4._____expensive car your uncle bought yesterday
A.what anB.what C.how an D.how