A) Family is the most important thing in life
Did either of the sisters bring her umbrella?
Either is singular.
Theseus' actions most advance the development of the plot.
Parallel structure may be corrected by splitting infinitives
is false because there are times that you
can achieve parallel structure through using an infinitive.
To add, <span>in
traditional descriptions of English, the </span>infinitive<span> is the basic dictionary form of a verb when used
non-finitely, with or without the particle to. </span>