verb
1
BAD : His illness has caused him to lose a lot of lessons.
GOOD : His illness has caused him to miss a lot of lessons.
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If you do not attend a class, meeting, activity, etc, you miss it: 'If you don't hurry up, you'll miss your appointment.' 'I'd hate to miss one of John's parties.'
2
BAD : I don't care if they're lazy, as long as they don't lose my time.
GOOD : I don't care if they're lazy, as long as they don't waste my time.
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waste your/sb's time = (cause domeone to) spend an amount of time without doing anything useful: 'I wish they'd stop asking me silly questions and wasting my time.'
Compare: 'The puncture meant that we lost a lot of time.'