which ones correct?

[ho_jc]

Hi, would like to know the differences of the following:

1.
a) Exam in progress. Silent please
b) Exam in progress. Silent.
c) Exam in progress. Silence
d) Exam in progress. Silence please.

which one is more appropriate?

2. Home letter / letters home / letter home

3. Adults english / adult english

4. Heartiest congratulations or heartiest congratulation?
When do we use congratulations & congratulation?

thks

[5jj]

Hi, would like to know the differences of the following:

1.
a) Exam in progress. Silent please
b) Exam in progress. Silent.
c) Exam in progress. Silence Correct, but very firm
d) Exam in progress. Silence please.

2. Home letter / letters home / letter home More context would be helpful

3. Adults english / adult english More context would be helpful

4. Heartiest congratulations or heartiest congratulation?
When do we use congratulations almost always & congratulation almost never

5

[BobK]

Incidentally, your 'which ones correct' was missing a verb: 'which ones are correct.?' (Or perhaps something else was missing...)
b

[ho_jc]

thk you for the reply.

English for adults-- do we say adult english or adults english?
Letter from home--letters home or home letter?

For me, i think should be adult english & home letter(s). we use adult as adj that explain what type of english class, home as adj to mention what kind of letter.

but i read from book it says letters home, which made me confuse. can someone explain?