what is the difference between on the top of and at the top of? Thanks

I left my keys behind in the office. Is this sentence correct? Thanks.

Clive wrote: Hi, Very generally speaking, minutes are intended to record what happened at the meeting, so past tense is the most obvious choice. Best wishes, Clive During the meeting, we discussed some future plans and

Can I use the present tense when doing the minutes? Thanks

There are six charis in a discussion room. A guest walks into the room and then I say to him 'you can take any seat you like'. Is it okay to say ' you can take any seat you like'? Thanks

It is okay/good. That is okay/good. Any difference between these two sentences? Thanks

Below is a question that I found in a survey. You go to the library/bookstores very often looking at books. I am wondering whether the article 'the' is needed in the sentence. What do you think? Thanks.

Mister Micawber wrote: Use ' to '. I see it-- generally-- as: This is an introduction to X = this introduces X. This is an introduction of X = this X is introduced. I will give you an introduction of my micro-teaching. I will give you an

This is an introduction of my micro-teaching or introduction to my micro-teaching. This is an introduction of my reserach study or introduction to my reserach study. Which prep is correct? Any difference between 'introduction of something'

Some students are sleeping in the class. The teacher asks them not to lie down on the table. Is it correct say 'not lie down on the table'?