"지금 하면 안되요" => 지금 하면 안 돼요. => You shouldn't do it now. -면 in 하면 is one of the verb connective forms. It expresses a conditional situation, like "if ...". 하면 is constructed as 하다 + -면, where 하다 means to do, to perform, and many other related things. 하면 thus means "if you do ...". It is usually used with a noun indicating the activity or deed before it. Here are some examples: - 그렇게 하면 안 돼. It's not right to [if you] do it that way = You shouldn't do it like that. - 내가 노래를 하면 내 남동생은 웃으며 따라한다. If I sing, my little brother smiles and sings along. - 내일 비가 오면 어떡하지? What should I do if it rains tomorrow? (오다 -> 오면) - 지금 하면 안 돼요. You shouldn't do it now. - 지금 하면 안 돼요? Is it not okay to do it now? = Can't I do it now? The last two examples are not mentioning what it is talking about, with the assumption the speaker and listener already know that. So they are not good sentences to use in isolation.