Use of "too"

[Tom]

Hello everbody

I am a bit confused

Have you ever noticed that sometimes too comes at the end of a sentence following a comma and sometimes not.(Examples are following)? Is it optional?

1- A lot of time is needed , too.
2- He was killed too.

Why comma in the first and why not in the second?Please help me understand it thoroughly.

Ever yours

Tom

[Mister Micawber]

.
Some think it is required and others do not (especially in short statements). To be careful, use the comma in essays and tests.
.
_________________
Canadian-American native speaker
who teaches English for a living at Mister Micawber's
ESL cafe: Interview with Mister Micawber