Punctuation help

My one desire is this: to live a good Christian life.

(I believe the word "to" should be cap.)

Don’t you agree that our team is the best in the league?
(I think this one is ok)

More than forty people were killed in the airplane crash. What a terrible tragedy! ( I also think this is punctuated correctly)

Be sure to take the following items when you go camping: a torch, matches, and a first aid kit.
( should the word A be capital?)

There is only one other possibility-to travel by air. ( should I use a comma between possibility and travel?)

He asked me where the library was? (This should be a period)

To do satisfactory work, is my aim. ( I don't know about the comma here)

[RonBee]

Re:

• My one desire is this: to live a good Christian life.

That is perfect. Do not capitalize the first word of a phrase following a colon.

Re:

• Be sure to take the following items when you go camping: a torch, matches, and a first aid kit.

That is exactly right.

Re:

• There is only one other possibility-to travel by air.

That should be a dash instead of a hyphen.

Re:

• He asked me where the library was?

That's not a question but a statement. Replace the QM with a period.

Re:

• To do satisfactory work, is my aim.

The comma is there for no good reason. Delete it. (Never put a comma between subject and verb.)

[ue_bugmenot]

Make it a great day, with flowers!

Is it correct to put a comma after "day"?