The semi-colon ";" is used when a greater pause is required than that shown by the comma.
(i) It is used to separate constituent parts of a compound sentence from one another.
As Caesar loved me, I weep for him; as he was fortunate, I rejoice at it; as he was valiant, I honor him; but as he was ambitious, I slew him.
(ii) It is used to separate a series of loosely connected clauses.
Reading maketh a full man; speaking a ready man; writing an exact man.
The colon ":" may be used at the writers own discretion. If he thinks that the pause is not sufficiently marked by a semi-colon, the colon is used.
(i) It may introduce an additional remark in explanation or in confirmation of an earlier statement:
Always take good care of your health:
There is no happiness in life without it.
(ii) It may be used to introduce a quotation. It is often followed by a dash: Shakespeare wrote: "Frailty thy name is woman".
(iii) It may be used to introduce a series of clause.
We must know the various uses of glass: we make mirrors; it is used for making lenses; it is used in windows to protect us against wind and dust.
A Note of interrogation "?" is used after sentences which ask a question. It serves at the end of the sentence and thereby the sentences that follow must
begin with a capital.
What did he do? We want to know that.
A Note of Exclamation "!" is used after word/words or sentences which express emotion:
Nonsense! I don't believe it.
Oh my God! He failed again.
What a great man he was!