Questions about example sentences with, and the definition and usage of "Covering"

A:
As a journalist, the speaker’s job is to talk with politicians, who often lie.

So the speaker is saying that they don’t need to hear more lies from who they are speaking to now.

A: 不，这意味着他或她覆盖了手机
Bù, zhè yìwèizhe tā huò tā fùgàile shǒujī

A: Your partner is giving advice. Basically he is saying:
- You can leave the spreadsheet alone. In the text of the email, though, it would be helpful to explain that positive means decreased expenses.

A: × You'are covering my view so I can't see anything.
✓ You're covering my view so I can't see anything.

It's almost perfect ~

A: Because of its covering many fields such as electronics,power system and so forth,………

It would sound better as,

Because it covers many fields, such as electronics.. etc.

A: For the winter (as it is KNOWN winter, i.e. the next winter)

A: Your sentence makes sense, I would just say cover letter instead of covering letter
describe yourself instead of describe your person
and it must/should be sent instead of it has to be sent