Use double spacing and wide margins to leave room for comments.用双倍行距和宽松的页边空白，这样可以有地方写评注。All essays must be typed and double-spaced.所有文章必须用双倍行距打出来。Be sure to double-space. It makes reading much easier.务必用双倍行距。这样方便阅读。The seedlings were planted in regular rows.树苗按固定行距种植。