把下面句子合并成一句。

Tom is the boy．I went to the cinema with him together．

把下面句子合并成一句。

The book is written by that famous writer．I am very interested in it．

把下面句子合并成一句。

John is a very kind-hearted man．You can turn to him for help．

在下面定语从句中，用适当的介词填空。

He bought a book yesterday, the author ________ which is a teacher．

在下面定语从句中，用适当的介词填空。

The desk ________ which Jack is leaning is John’s．

在下面定语从句中，用适当的介词填空。

Ours is a beautiful school, ________ which we are proud．

在下面定语从句中，用适当的介词填空。

Do you know the building ________ which is flying a red flag?

在下面定语从句中，用适当的介词填空。

His bike ________ which he went to work was stolen last night．

在下面定语从句中，用适当的介词填空。

The age ________ which children can go to school is seven．

在下面定语从句中，用适当的介词填空。

I was surprised at the way ________ which he treated the old man．