These words are often confused especially by the use of comprise for compose. A body comprises (or consists of) the elements of which it is composed (or constituted); in the first example, for instance, Opus 77 comprises the quartettes, not the other way round. Compose or constitute or form should have been used in all examples.
The two quartettes comprising Handel's Opus 77.
The smaller Regional Hospitals which comprise a large proportion of those available to Regional Boards.
The twelve Foreign Ministers who comprise the Atlantic Treaty Council.