请教2道语法题

zuzu1116

1）Cyclamates were introduced in the early 1950's as alternative sweeters for use by individuals who needed reducing their sugar intake for medical reasons.

2)The layers of an elephant's tusk are deposited from the pulp, yet that the innermost layer is the newest.

这两道都是PP上的，该如何改呢？

Sunday

1,D, to reduce; need reducing 是被动

2,C, yet 是副词，不是连词，所以在yet前还要加个连词连接2个句子。

amanda_wang

yet 可以做连词啊～是不是应该be deposited by啊？

zuzu1116

查了字典yet是连词，到底应该改那个？