1. Can
1.1. hability or possibility
1.1.1. Example
1.2. In interrogative sentences , the use of "can" may request permission
1.2.1. Example: I can drink a glass of water ?
2. could
2.1. hability or possibility in the past
2.1.1. Example: I couldn’t sleep last night
2.2. for future possibilities
2.2.1. Example: I think it could rain later
3. may
3.1. As "could" used "may" to indicate possibilities in the future
3.1.1. Example: I would bring an umbrella, it may rain later
3.2. It can also be used to give permission or instructions
3.2.1. Example: You may use your cell phones now.
3.3. In interrogative sentences , the use of "may" is more polite than "can" or "could "
3.3.1. Example: May I leave now?
4. might
4.1. possibilities in the present or the future. In these cases, it is synonymous with "may" .
4.1.1. Example: It might be better to finish this now, rather than wait until tomorrow
4.2. It can also be used as "may" , to ask permission or make polite requests , although this use is much more common in the UK than in the United States.
5. will
5.1. the use of "will" means will or determination.
5.1.1. Example: We will learn English
5.2. interrogative sentences information , a favor or options.
5.2.1. Example: Will you help me move?
6. shall
6.1. "Shall" is used as the "will" to form the future tense . The use of " shall" is much more common in the UK and is generally more polite.
6.1.1. Example: Ricky shall be happy to see you
6.2. You can also use "shall" for offers and suggestions or to ask about options or preferences .
6.2.1. Example 1: Shall l we meet at 10pm?
6.2.2. Example 2: Shall we go to the movies or a museum?
7. should
7.1. "Should " indicates an obligation or recommendation. It reflects an opinion on what is right . It translates as the conditional "should" in Spanish .
7.1.1. Example: You shouldn’t work so hard
7.2. "It should " is used in interrogative sentences to ask if there is an obligation or to ask for a recommendation .
7.2.1. Example 1: Should we leave a tip?
7.2.2. Example 2: Where should they meet you?
8. ought to
8.1. " Ought to " is synonymous with "should" .
8.1.1. Example: She ought to quit smoking
8.2. Note : Never "ought to " is used in interrogative sentences in American English .
9. must/have to
9.1. "Must" indicates an obligation, prohibition or need. You can also use "have to" (have to) .
9.1.1. Example 1: You must [have to] brush your teeth two times a day.
9.1.2. Example 2: You must not drink and drive
9.1.3. Example 3: When must we meet you?
9.2. You can also use "must" to indicate probability or take something
9.2.1. Example: David not here. He must be sick because he never misses class
9.3. You may also use "must" for rhetorical questions.
9.3.1. Example: Must you always be late?
10. would
10.1. "Would" is used to declare a preference and to ask for something politely.
10.1.1. Example 1: Would you help me please?
10.1.2. Example 2: When would you like to go to the movies?