精选优质文档-倾情为你奉上北大2013年考博士英语真题及答案Part Two: Structure and Written Expression20Directions: In each question decide which of four choices given will most suitably complete the sentence if inserted at the place marked. Mark your choices on the ANSWERSHEET.21.The nuclear family _ a self-contained, self-satisfying unit composed of father, mother and children.A. refers toB. definesC. describesD. devotes to22.Some polls show that roughly two-thirds of the general public believe
