I.单句语法填空 1.Moderm science has given clear evidence that smoking can lead_tomanydiseases. 2.The physics problem remained _ confusing (confuse) to the boy although explainedover and over. 3.Six days later, the police anrested him and charged him with murder. 4.I'll ask the teacher about the attributive clause.I'm very puzzled (puzzle) about it.