Choose the right option. We ....... (usually/meet) in the library at three o'clock.

The correct answer is 'usually meet'. The sentence describes a habitual action, something that happens regularly. In English, we use the present simple tense with adverbs of frequency (like 'usually') to talk about habits or routines. Therefore, the correct option is 'usually meet', which is the present simple form of the verb 'meet' with the adverb 'usually' in the correct position. Explanation of why other options are not correct: * 'do usually meet': This option is grammatically incorrect, it is not used in this case. * 'are usually meeting': This option uses the present continuous tense, which is used for actions happening at the moment or temporary actions, not for habits. * 'is usually meeting': This option is incorrect because 'we' is a plural subject and requires a plural verb form, not 'is'. Final Answer: usually meet.