Generally speaking, a computer works _______________ a human brain.
---- Is that girl Susan?---- It ______ be her. She left for Beijing yesterday.
----Shall we go to the amusement park this Sunday, mum?---- Sure, ________ I am busy.
This is the third time the famous scientist __________ the United States.
----Philip has gone to New Zealand.----Oh,can you tell me________?
No one can achieve success __________ effort.