Past progressive 

Most of the time you can use both with no difference in meaning. It's not an area where students make noticeable errors, so I wouldn't worry about it too much.

Teacher Dan's videos thank u so much sir...

same meaning. 'before going to bed' is a reduced adverb clause.

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and sir pliz will u kindly clerify my doubt on present progressive and future progressive usage for making plans

past progressive: 'at 10:15, Dan was typing on his computer.' -action was in progress at that time (10:15) past perfect progressive: At 10:15, Dan had been typing for 15 minutes. -action started 15 minutes before 10:15 and continued to 10:15. -past perfect progressive stresses 'how long'

Teacher Dan's videos thank u so much sir

Thank you so much 👍👍👍👍👍👍