请简要说明理由
1.The food in the restaurant is good ______ the price is too ______.
A.and ; high B.but ; high C.but ; expensive D.because ; low
4.I think a dog is a good pet for _________ child.
A.a 6-year-old B.an 6-years-old C.a 6-year old D.a 6 years-old