问题补充：
--Surfing first started on the islands of Hawaii, didn it?
--Yes, but now it by people all over the world.
A. is enjoyed
B. is enjoying
C. has enjoyed
D. will enjoy
答案：
(答案→)A. is enjoyed
B. is enjoying
C. has enjoyed
D. will enjoy
解析：此题考查一般现在时被动语态的基本构成。
