Thesearethethings.Iboughtthemyesterday.Theyarethepeople.Isawthemyesterday.怎么样把这两个句子像“ThisisthebookwhichIboughtyesterday.”这样连起来?这种句子叫什么句?顺便帮忙看看有没有写错：Thisist

　　Thesearethethings.Iboughtthemyesterday.

　　Theyarethepeople.Isawthemyesterday.

　　怎么样把这两个句子像“ThisisthebookwhichIboughtyesterday.”这样连起来?这种句子叫什么句?顺便帮忙看看有没有写错：

　　Thisisthecarwhichthemechanicrepairedityesterday.

　　HeisthemanwhomIinvitedtotheparty.

　　Heisthemanwhocameherelastweek.

　　Sheisthenursewholookafterme.

　　Heisthepolicemanwhocaughtthethieves.

　　SheisthewomanwhomImetheryesterday.

　　Iamthepersonwhowrotetoyou.

　　一时粗心没看到。

　　不过开头问的那两个句子该怎么做啊，我们还没有学这个。例句里只给了单个物品改用的“which”，就是不知道数量多的话该用哪个。