Explanations
1. dress up装扮;乔装打扮.
Dress up常与as, in连用构成短语:
dress up as...意为“装扮/乔装打扮成..”
dress up in...意为“穿上...”后接表示衣服或颜色的名词。
He likes to dress up as a soldier.
他喜欢装扮成军人。

On Christmas Day we always dress up in red.
在圣诞节我们总是穿上红衣服。
辨析: dress, wear, put on, haveon与be in
Dress“给某人穿衣服”，其宾语是人或反身代词，不是表示衣服等的名词
Wear“穿着;戴着”强调状态
Puton“穿.上;戴着”强调动作
Have on“穿着;戴着”强调状态。不能用于被动语态。
Be in“穿着;戴着”强调状态，通常接表示颜色的名词。

She dressed her son and then sent him to school.
她给儿子穿好衣服并送他去，上学。
She wears red shoes.
她穿着红色的鞋子。
He put on his best clothes for the party. .
为参加晚会他穿上了最好的衣服。
She had a beautiful new suit on.
她穿着一套漂亮的新衣服。
Who is the girl in red over there?
那边穿红衣服的那个女孩是谁?