It's a matter of style -- which is to be expected in a book named the elements of style -- to leave out the first 'and'; you could put it there, but it is not required. Without it the sentence "runs better". The last part of the sentence adds to the description given before, saying it in different words.
New words, one handy idiom, and a 2-minute quiz — delivered to your inbox to keep your streak alive.
Clive'err' is fine as written.
Here's the idea.
The intent is to suggest that . . . the beginner (should) err on the side of conservatism .
ferdisSubjunctive, right? I always make mistakes with thatYou and 90% of native speakers.