Of course not. You cannot work in Singapore with a visitor's visa. This would be illegal. You have to apply for a Singapore work visa.
Depends what visa and what country
Nobody can work in the visa on a visitor visa. Short duration courses like cookery class that will not add any credits to a course can be attended using a visitor visa. But working in the US, that will enable you to draw salary is not allowed on a visitor visa.
If for some reason you are stopped by border security, your visitor's visa will not take precedence.
Yes! U Can!
A passport and depending on the visitor's country of origin, a visa.
You should apply at the INS to renew your visa. Otherwise, you have to go back to your country of nationality and apply for a new US visa. If you don`t, you may be deported and may have to pay a penalty fee.
Visitor
in the visitor's visa
It depends on what it says on your entry visa. If you enter the UK on a visitor's visa, it usually allows you to stay for six months, after which you have to leave.
Does not matter if you are a US Green Card holder or not, when you have an Australian visitor visa, you can go there.
by going to the bank and ask to renew it