Discard the water layer, which contains the aspirin or acetominophen) and evaporate the chloroform layer to dryness under gentle heat. The result is codeine base, a white crystalline powder. Combine 20 mL pyridine and 25 mL conc. HCl in a beaker and heat strongly to 190C to drive off any water.
A simple sentence usually consists of a single finite clause with a finite verb that is independent. More complex sentences may contain multiple clauses. Main clauses (i.e. matrix clauses, independent clauses) are those that can stand alone as a sentence. Subordinate clauses (i.e. embedded clauses, dependent clauses) are those that would be awkward or incomplete alone.
A dependent person needs to lean on someone stronger. A dependent clause is one that cannot stand on its own two feet--it needs an independent clause to lean on. You must join a dependent clause to an independent one. This is called subordination. Independent clauses are strong Compare an independent clause to the ideal roommate: She cleans up after herself, pays her share of the bills, never forgets to turn off the iron, and can fix a leaky faucet.