are these sentences correct?/
1.这是办公室吗？
2.我在这办公室办公
3.我住十七楼
4.我知道他的手机号码
5.他的电话是六零三一

Question

are these sentences correct?/
1.这是办公室吗？
2.我在这办公室办公
3.我住十七楼
4.我知道他的手机号码
5.他的电话是六零三一

Answer

The first sentence has a small mistake, for no one will say like that.

I will say:
这是XXX办公室吗？

xxx means a word to describe 办公室

Answer

yes,it's all right! your chinese is good,haha.