题目内容：

she often appears on the stage as a young girl.she must appear in a bright red dress
这两句中一个appear 作为第三人称加了S.但是后面一句当中为什么没加S?

优质解答

因为第二个appear前加了一个must,must又是一个情态动词,情态动词后边加动词要用动词原型,不管第几人称.即使是过去式,也是情态动词变过去式.记住就行了,情态动词后边加动词原型.