两题

cocool

1.The distinctive hereditary tartans (that are alleged to be worn) since antiquity by members of the Highland clans were in fact designed by Scottish woolen manufacturers in the eighteenth and nineteenth centuries.
正确答案:alleged to have been worn
整句为过去时,为什么还有一个have been?


2.By installing special electric pumps, (farmers'house could be heared by the warmth from cows' milk,according to one agricrltural engineer.)
正确答案:farmers, according to one africultural engineer could use the warmth from cows' milk to heat their houses.
by 是否表示被动,如是,A为什么不对?

lucylu

1.因为有since,所以用了完成时
2.因为By [U]installing special electric pumps[/U]的主语，及动作的发出者，只能是farmers,而不是farmer's house.
[em12]