According to public health officials, in 1998 Massachusetts became the first state in which more babies were born to women over the age of thirty than under it.
我补充这道题,大家也可以理解补充的概念GWD3-Q30:比较对象是cars,所以those要补出
Today’s technology allows manufacturers to make small cars more fuel-efficient now than at any time in their production history.
A. small cars more fuel-efficient now than at any time in their
B. small cars that are more fuel-efficient than they were at any time in their
C. small cars that are more fuel-efficient than those at any other time in
D. more fuel-efficient small cars than those at any other time in their
E. more fuel-efficient small cars now than at any time in
而咱们帖子里这道题的比较对象是age,在than的前后,under it又指代清楚,因此不需要补