1.错。应为:There are about two thousand workers in our factory. 解析:几千,几百的表达法是基数词加 thousand 或加 hundred , 而且均不要加 s 。这样的单位还有 dozen (打),score (20年)等。 2.错。应为:In the morning there are hundreds of old people walking in the park. 解析:当表达数百,数千时,要用 hundreds of 和 thousands of 这一结构。 3.错。应为:The class begins at 8 a.m. 解析:与符号或与缩写的字母连用时一定要用数字,如:43%, 67, No.2… 4.错。应为:Two fifths of the books are sold out. 解析:分数表示法,分子用基数词,分母用序数词,但分子大于1时,分母要在序数词后加s。