Lectures: you sit in a lecture hall usually with 100 or so other students listening to a lecturer read out notes/a presentation and you take notes. Sometimes, rarely, they ask a question.
Seminars: small groups - usually between about 10-20 people on my class, where you are expected to have done the reading/prep work ready to discuss in class - usually backs up the lecture topic
Workshops - more active classes, where you might work in groups, do presentations, work on a project or something. Similar size to seminars usually.
Personally, I don't have 'tutorials' but I believe they are pretty similar to seminars.
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