0201--9`30.

xkfy0521

9, Insulin is manufactured by specialized cells in the pancreas and
released------ glucose reaches a certain concentration in the
bloodstream.
A, which    B, whenever      C,how     D, during

横线后面是个完整的句子，所以找个连词，而during后面不能加句子。

30, Harbors are (protected) areas (of water) that can be (used the) transfer of passengers and cargo (between) ships and shore.

C错， 改成used by the？ are protected 后可接宾语？

protected做定语，C改成be used for