From time to time a crocodile has snatched someone _______ he or she is even aware that the crocodile is there.

A. when                              B. until                        C. since                              D. before

From time to time a crocodile has snatched someone ______ he or she is even aware that the crocodile is there.

1. A.
   when
2. B.
   until
3. C.
   since
4. D.
   before

From time to time a wave burst over the boat and swept over him, but he kept ________ for ten minutes．

1. A.
   to work
2. B.
   to working
3. C.
   working
4. D.
   on work

From time to time a crocodile has snatched someone _______ he or she is even aware that the crocodile is there.

A. when                             B. until                 C. since                      D. before

From time to time a crocodile has snatched someone _______ he or she is even       aware     that the crocodile is there.

       A. when                       B. until                        C. since                 D. before