The new discovery _______ be of great service to mankind.
A
beboundto：注定要，一定会。本题中主语是Thenewdiscovery，所以谓语动词要用is。句意：这项新发现对于人类必定大有用处。
He would have given you more help, if he ________ so busy.
Whenyou're_____acrisis,itoftenhelpstotalktosomeone.
The professor asked a question, and David ________ a good answer.
Because of the bad weather, the sports meet had to be ________.
The central theatre has a seating ________ of more than 3, 000 people.