单选题：Why _______ you be so stubborn? You should think over my ad..

You are certain to live your dream _____ you make great efforts and lay emphasis on improvements in efficiency.A. on condition thatB. as far asC. even though D. in case

There were some chairs left over _____ everyone had sat down.A. when B. until C. that D. where

—Hey! Any idea about learning abroad?—You ________ google the College Board to learn the names of colleges you ________ be interested in.A．may; need B．can; mightC．will; should D．shall; must

—I regret to say that I failed to rank first in the terminal exam.—Come on，nobody ________ win all the time.A．shouldB．mustC．shallD．can

_____ they decide which college to go to, students should research the admission procedures.A. As B. WhileC. UntilD. Once