_________ happened to be no one in the building when the fire broke out.
253. I have to wear a _____ and a tie in order to work in the manager’s office.
252. One of the purposes of United Nations is to achieve international co-operation without distinction as to race,____, language or religion.
251. The America’s selling weapons to Taiwan cast a shadow on the Sino-U.S relationship. Which of the following can explain the underlined part?
250. Every year Harvard University awards to excellent foreign students in theoretical physics.
249. A_____ has taught us what atoms are made up of and how powerful the atom bomb is.