Contoh soal:

2. The dolphin uses whistles and clicks whose complexity continues to fascinate researchers.

A. Dolphins’ whistles and clicks have been studied by the interested researchers.

B. The complexity of dolphins’ whistles and clicks continues to puzzle researchers.

C. Researchers remain interested by the intricate nature of dolphin’s whistles and clicks.

D. Researchers continue to try to study the intricate nature of dolphins’ whistles and clicks.