three meters long? tree-meter long? three-meter-long?

Dear teachers,
in the following sentence,
It is _______
a. three meters long
b. three-meter long
c. three-meter-long
which one is the answer?
what's the difference between them?
In my opinion, both a and b are correct, and choice C can only be used as modifier, e.g. three-meter-long desk. but I am not sure, and can A and B be used as modifiers?

I'm puzzled, Please help me out.
thanks.

by the way, "He ate two thirds of the pears","He ate two-thirds of the pears."
which one is right? two thirds or two-thirds
is the hiphen(-) a must?

Hello JJ

I would say that only A is correct, in your example.

1. It is three meters long ] fine.

B and C may be used as compound adjectives, e.g.

2. It is a three-meter-long fishing rod ] fine.

(Some people would dislike the partly hyphenated C.)

As for "two thirds/two-thirds", you'll find both forms. The prevailing tendency in everyday written English is to omit hyphens wherever there isn't a possibility of confusion. But in a more serious publication, you would probably find it written "two-thirds".

MrP

Hello, MrP. I have a question related to that of JJ. (I suppose the answer is very easy and I should know it, but I am a self-taught person [in general, althouh I took some classes in past], so I sometimes don't know basic principles.) Should we write "forty-four" of "forty four"? MS Word spelling checker always suggests the first one.

Thanks in advance,
Nyggus 8-)

Hello Nyggus

The usual practice in books, magazines, etc. is to hyphenate; but many native speakers do omit the hyphen, in emails, memos, etc.

See you later,
MrP