_______it took 200 years to move from the steam engine to the Internet, there could be major development in _______ are now considered frontiers(尖端) of science in just the past few ten years.

Once he makes a promise, he will ______ it.

Who can tell me the ________ to the question

Do you know if Jack will drive to London this weekend–Jack Never! He_____ driving so far.

His friend is ________honest boy. He is _______best student in their class.