When it it appropriate to use the word "law" and appropriate to use the word "laws"?
for example, a Bachelor of Laws, civil and commercial law, etc.
Civil law refers to that body of law in general, but you can count individual laws that are enacted.
PS Please be patient- people come in as volunteers, from different time zones, and there are many questions posted every day.
Welcome to the forums, InterMFU.
Bachelor of Laws is a special case, and something of an anachronism.
'Historically, law students studied both canon law and civil law.' (Wikipedia)
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What you call a bachelor's degree is dependent entirely on what it is officially called by the awarding body.
An "LLB" is a Bachelor of Laws (the double 'L' signifies a plural). If it's called a B.Law, then you wouldn't use the plural.