【正确答案】正确答案：(1)Jack put his ball. This sentence is ungrammatical because it is incomplete, for " put" means " move sth. /sb. in a special place" , but this sentence does not indicate where to "put his ball".(2 points) (2)I wonder Michael walked the dog. The meaning of this sentence is incomplete; an "if" should be added to the object clause of "wonder".(2 points) (3)Frank thinks himself is a superstar. In this sentence, the subject of the object clause " himself is a superstar" is ungrammatical. A subject should be in nominative case.(2 points)

【答案解析】解析：三个句子中，第一句中的“put”指的是“将某物／人放在某处”，故该句不完整，没说明将“his ball”放在何处；第二句句意不完整；第三句中，宾语从句的主语应该用主格，而该句中却错用了反身代词的宾格形式。