Learn French: Nous avons besoin d'une poutre de quatre mètres de long.

Nous avons besoin d'une poutre de quatre mètres de long.

We need a beam four meters long.

Breakdown of Nous avons besoin d'une poutre de quatre mètres de long.

une

a / an (feminine)

nous

we / us (object pronoun)

of / from / any (in negative sentences) / about (concerning)

quatre

four

Questions & Answers about Nous avons besoin d'une poutre de quatre mètres de long.

Why are there two instances of 'de' in 'une poutre de quatre mètres de long'?

This is the standard French formula for physical dimensions: Noun + de + Measurement + de + Dimension. The first de links the object to its measurement (une poutre de quatre mètres), and the second de specifies which dimension is being measured (de long).

Can I use the noun 'longueur' instead of 'long' at the end of the sentence?

Yes, absolutely. For length, width, and height, you can use either the masculine adjective or the noun after the final de. Both de long and de longueur are perfectly natural ways to say 'in length'.

Why is it 'd'une poutre' rather than just 'une poutre'?

The French expression for 'to need' is avoir besoin de (literally, 'to have need of'). Because une starts with a vowel, the de drops its 'e' and contracts to d'. Even though English just says 'need a beam', French requires that preposition.

Could I use a verb instead of prepositions to describe the beam's length?

Yes, the verb faire is frequently used for measurements. You could rephrase this as une poutre qui fait quatre mètres de long (literally, 'a beam that makes four meters in length'). You still keep the de before the dimension word!