You need to know about correct usage of words. Here are four sets of words about which even experienced freelance journalists can get confused over correct usage:
shall / will In grammar shall is called “simple future tense”. But these days shall is usually replaced by will. Such as “They will win” or “She will walk”. But many writers still use shall in first-person questions such as “Shall I speak?” or “Shall we fly?” And of course in expressions of determination it sounds good to use shall such as in “We shall overcome!” or “Goodness shall triumph!”.
should / would Should can indicate obligation, such as “She should stop eating so much” or “They should stay away”. Should can indicate advice, such as “He should think again” or “She should check it again”. Should can indicate a likely event, such as “She should win this time” or “He should make a lot of money this year”. Should can indicate a remote possibility, such as “Should he drop dead, ignore him” or “Should he lose, he will never forgive you”. Should can be used emphatically, such as “I should think so!” or “I should be so lucky!” Would is used as the past tense of will, such as “He would come to this house often” or “She would always speak her mind”. Would can indicate something conditional, such as “It would be a peaceful death” or “I would win every time if I concentrated”. Would can be used politely, such as “Would you like ice-cream next” or “I would not like to comment”.
may / might May indicates uncertainty about the future, such as “The leader may sack him” or “The son may inherit the lot”. Might is the past tense of may, such as “The leader might have sacked him if he hadn’t improved” or “The son might have inherited the lot if the daughter had not challenged the will”.
can / could Can is present tense and could is past tense. Can and could express ability, such as “She can use a computer” or “He can cook in the French style”. Can and could do not assess probability as in “The leader may sack him” or “The leader might have sacked him”.