comma

Hi there,

Quite a number of writers, even native speakers, will put a comma before the words such as 'although', 'though' and 'because'. But I was taught not to put a comma before these words. Is it true?

Simon

hi there,

how about the comma before 'though'? unnecesary?

Aspiring to be an advanced knowledge economy, Beijing needs the great majority, if not all, of our students to success, academically and professionally, though individuals may attain achievement at differeent paces.

Simon