One writing question
A poetic form congenial to Robert Browning was the dramatic [monologue, it let him]explore a character’s mind without the simplifications demanded by stage productions.
(B) monologue, which let him explore
(C) monologue that lets him explore
the answer is B and I know why C is wrong
but the thing is I don't understand why "let" is in the past tense, and "lets" is in the present tense. Isn't "lets" singular??