同学你好，该知识点来自沪江网校《新概念英语1、2、3、4册连读【限时特惠班】》的课程，想要更系统的学习，欢迎进入课程学习。不仅可以和更多的同学一起学习，而且还有老师、助教随时的学习指导和知识点解答哦。

同学你好~
say to sb后面一般不加从句，而可以加直接引语，所以在这里不合适。
I just said to him 'you must be mental'.
我刚才对他说：“你一定是疯了。”
'He speaks English,' she said to Graham. 'I gathered that.'
“他会说英语，”她对格雷厄姆说，“我料到了。”

had better后面要加动词原形，这是一个固定搭配，所以arrive保持原形。
He thought he had better track this wolf and kill it
他认为最好跟踪这只狼，杀了它。
George caught the look and decided that Bess had better leave before she exploded.
乔治看到这一表情，认为最好让贝丝在发作之前离开。

祝同学学习进步~