Learn Turkish: Çok iş yapmak zor. - Doing a lot of work is hard.

In Turkish, the infinitive form of a verb (ending in -mak or -mek) acts like a noun. This means yapmak translates to both "to do" and "doing". In this sentence, the entire phrase çok iş yapmak (doing a lot of work) is the subject.

If it means "a lot of work", why isn't the word iş plural?

In Turkish, when you use a quantity word like çok (a lot of, many) or a number, the noun that follows it stays singular. So it is always çok iş, never çok işler.

Could çok mean "very" in this sentence?

Çok can mean "very" or "a lot of" depending on what it sits next to. Because it is right in front of the noun iş (work), it means "a lot of". If you wanted to say "Doing work is very hard", you would move it right in front of the adjective: İş yapmak çok zor.

Where is the word for "is"?

There isn't one! In Turkish, you usually don't need a word for "is" in simple present-tense statements. You just state the subject (çok iş yapmak) followed by the adjective (zor), and the "is" is automatically understood.