Is you've a noun pronoun or a verb

as much wood as a woodchuck could chuck if a woodchuck could chuck wood.

sadly it cannot chuck wood

right angles are formed by perpendicular lines. if the lines would extend, to make two intersecting lines, they would form four right angles.

the pronoun reference replaces a noun, but you have to make sure there's no room for confusion.

in the first sentence "her" could be referring to shely or to the sister. the answer there is "shelly called her sister and told her about the new baby."

in the second sentence "it" could be referring to the roof or the floor. the answer there is "since the roof leaks on the family room floor, we need to repair the roof."