hop in (to) exp.  (very popular) to enter
;to enter by jumping on one feet : if you want a ride to school, hop in!
to hop in on exp. if you want aride to school hope on in.
note: if the preposition "in" is omitted from this expression ("to hop in"), it takes on the meaning of "to mount". want to ride my bike? hop on.
want to ride my bike? climb up!

"I hear ya "  exp. "I agree with you." Note: in this expression, it is common to use "ya" which is common pronunciation of "you."

"Holy cow! " exclam ( exclamation of astonishment). holy cow! that was unbelievable!  synonym: "Holy Toledo" exp. holy toledo!  that was unbelievable