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。

My glasses, ________ which I was like a blind man, fell to the ground and broke．

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。

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