定语从句掌握的好的速进

this is the bike which he gave to me as a present

This is the bike that he gave me as a present.(1.to 可以不要.give sb.sth.)
this is the bike which he gave to me as a present (2.to可以要give sth.to sb)

This is the bike that he gave to me as a present .

This is the bike that/which he gave to me as a present.to可以省略，因为give sth. to sb.=give sb. sth.好好学哟！

this is the bike which he gave it to to me as a present
give sth. to sb.=give sb. sth.
gave it to to me =give sth. to sb
不能省略

this is the bike which he gave to me as a present 。to当然要，定语从句中的句子要是完整的，不能有缺漏的，尤其是叫你把两个句子合成一句时，你可以一个词一个词的对照，看看有没有少