Correct your English

Number 2 is correct. The correct conjunction for number 1 is "as long as". As long as you work hard, you can pass the examination.

number 1 is the correct one if you say "Unless you work hard" it gives a condition or rather a cause and the effect of that cause is "you can pass the examination". I hope I gave the right explanation.

No doubt 2nd is correct. In the first sentence, unless should be replaced by if for the sentence to become valid.

Unless you work hard, you cannot pass the examination. They're both negative. Let's try both positive: If you work hard, you can pass the examination.

"Unless you work hard, you cannot pass the examination" -- is the correct sentence Since the verb in the second part of the sentence, under your example number 1, was preceded by can, which is to "pass" it is just right to use the conditional "if" and not unless.

The correct answer is unless you work hard you cannot pass the examination. The first sentence is wrong. What is the name of the book you bought? Are you teaching yourself English? Where are you from? I am sure there are simpler books that will give you a better introduction in English.

Number 2 is the right one here. "Unless you work hard, you cannot pass the examination", unless "working hard" here means not passing the examination. Then, it would mean the other way around: "If you work hard, you will not pass the exam". Hmmm, sounds like motivation from a classmate encouraging you to cheat instead. It's great to know that you're studying and using mylot at the same time.

I am sorry, I don't want to answer, because 'I don't know the correct answer". But, frankly speaking I thieve to know what is the correct one. Thank you for this post, it has added my knowledge about this grammar. Best wishes,