Ill sentences refer to sentences with grammatical, rhetorical or logical defects. Any sentence that violates the rules of grammatical structure or objective facts is a sick sentence. The former is called grammatical error and the latter is called logical error.
Common types of ill sentences are:
(1) is out of order;
(2) Improper collocation;
(3) Incomplete or redundant components;
(4) the structure is chaotic;
(5) the ideographic meaning is unknown;
(6) illogical;
(7) fuzziness;
(8) Mixed sentences;
(9) Improper classification.