This pair of socks ______ worn out. I'll have to buy a new ______.

I have__________new socks．

1. A.
   apair of
2. B.
   a pairs of
3. C.
   twopairs
4. D.
   two pair of

This pair of socks ______ worn out. I'll have to buy a new ______.

1. A.
   is, one
2. B.
   are, ones
3. C.
   is, pair
4. D.
   are, pairs

A．a pair of　　  B．a pairs of　　 C．two pairs    D．two pair of