请选择CBA*f1H4q7M9J+^/C'F0w:A)r:d I can see some ducks in the river.-S'a2n:W6b+q
A. swims-S'a2n:W6b+q
B. swimming-S'a2n:W6b+q
C. to swim-S'a2n:W6b+q