ISE:
1、Jerome often referred to art history textbooks while he was sculpting ; whenever he learned a new method in art class,he seeks out the work of sculptors who had used it in the past
A to
B while he
C seeks out
D had used it 这题主要不是很懂whenever的用法
IS:
2、The shift from traditional to cosmetic dentistry [ is because adults are getting fewer cavities and becoming more vain ]
A is because adults are getting fewer cavities and becoming
D is occurring because adults are getting fewer cavities and becoming
不是很明白A和D的不同