同学你好，该知识点来自沪江网校《英语零基础直达大学六级【随到随学班】》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~
第一句是对的，though的意思“尽管”，尽管他们是双胞胎兄弟，他们长得不像。
Anne was fond of Tim, though he often annoyed her.
安妮喜欢蒂姆，虽然他经常使她心烦。
Though she gave no sign, I was sure she had seen me.
尽管她没有示意，我还是确信她看见了我。


however的意思是“然而”或者“不管多么……”，在这个句子里都不通顺。
而且however引导从句，语序应该是：however+形容词或副词+主语+谓语。
However much he eats， he never gets fat. 不管他吃多少，他永远吃不胖。
However cold it is， he always goes swimming. 不管天有多冷，他都去游泳。

祝同学学习进步~