February to July, 1916.
April 6, 1917.
Monday, November 11, 1918.
(2) the abbreviations etc. and jr.
(3) non-restrictive relative clauses, that is, those which do not serve to identify or define the antecedent noun, and similar clauses introduced by conjunctions indicating time or place.
The audience, which had at first been indifferent, became more and more interested.
In this sentence the clause introduced by which does not serve to tell which of several possible audiences is meant; what audience is in question is supposed to be already known. The clause adds, parenthetically, a statement supplementing that in the main clause. The sentence is virtually a combination of two statements which might have been made independently:
The audience had at first been indifferent. It became more and more interested.
Compare the restrictive relative clause, not set off by commas, in the sentence,
The candidate who best meets these requirements will obtain the place.