Learn Russian: Огурец и помидор — овощи. - The cucumber and the tomato are vegetables.

In Russian, the present tense of the verb "to be" (am, is, are) is almost always skipped. When you are connecting two nouns to say one thing is another (like "cucumber and tomato = vegetables"), you use a long dash in writing and make a slight pause when speaking.

Why does овощи end in -и instead of the usual plural ending -ы?

The singular word for vegetable is овощ. Normally, masculine nouns ending in a consonant take -ы in the plural. However, Russian has a strict spelling rule: after the letter щ (and six other specific letters: г, к, х, ж, ч, ш), you must always write и instead of ы.

Are огурец and помидор singular or plural here?

They are in the singular form (a cucumber and a tomato). In Russian, it is very common to use the singular form of a plant, fruit, or vegetable to talk about the entire category in general. You could also use the plural forms (огурцы и помидоры) here and it would mean the exact same thing.

How do we know it means "the" cucumber and "the" tomato?

Russian does not have words for articles like "a", "an", or "the". The words огурец and помидор simply mean "cucumber" and "tomato". You have to figure out from the context whether it means a specific tomato, any tomato, or tomatoes in general. Here, the English translation adds "the" to make the general statement sound natural.