Minimal pairs are pairs of words that

1、（） are mounted in pairs to protect the

（） are mounted in pairs to protect the boiler against overpressure.ASafety valvesBWater tubesCSteam stop valvesDBlow down valve

2、碱基互补规律(complementary base pairing)

碱基互补规律(complementary base pairing)

3、He wears a pair of sunglasses（）（惟恐被别人认

He wears a pair of sunglasses（）（惟恐被别人认出来）.

4、Twisted Pair双绞线

Twisted Pair双绞线

5、The external circumference of a pair o

The external circumference of a pair of main bearing shells is slightly larger than that of the bore of the housing which receives themThe difference is termed （）.AnipBnapCgapDli

6、The pair of words “lend”and “borrow”ar

The pair of words “lend”and “borrow”are（）.Agradable antonymsBconverse antonymsCco-hyponymsDsynonym