【15.~19.】
My cousins, Wendy and Daniel,   15.  my parents and me this summer. We all liked the beach very much,   16.   we went there one Sunday morning. We   17.   on the beach and found some beautiful sea shells.   18.    we had lunch, my cousins and I swam and played in the water. We even dived down and said hello to the colorful fish. They were beautiful. Then we were tired, so we came back and took a rest. The sky was blue, and the water was cool and clean. We   19.  at the beach.
 * dive 潛水
【題組】 15.
(A) visit
(B) visited
(C) were visiting
(D) were visited