二、介词的语法特点 Grammatical features
(一)不能单独使用。 They cannot be used alone.
(二)不能重叠。 They cannot be reduplicated.
(三)一般不能加动态助词“了、着、过”。 They cannot normally take aspectual particles 了、着、过.
(四)一般不能用正反式提问。 They cannot normally be turned into an affirmative + negative question.
