Research has shown that _________. A: Dropouts are substantially below Ph.D.'s in financial attainment B: the incentive factor is a minor one in regard to pursuing Ph.D. studies C: The Ph. D: candidate is likely to change his field of specialization if he drops outD. about one-third of those who start Ph.D. work do not complete the work to earn the degree

Many promising postgraduates are unwilling to pursue a PH.D. degree because _________.

Research has shown that ______. A: dropouts are substantially below Ph.D. s in financial attainment B: the incentive factor is a minor one in regard to pursuing Ph.D. studies C: the Ph. D: candidate is likely to change his field of specialization if he drops outD. about one-third of those who start Ph. D．work do not complete the work to earn the degree

is the highest university degree that is conferred after a course of study by universities in most countries. A: Associate degree B: Bachelor C: Master D: Ph.D.

Professor Chen complained that he had been unable to __________ any Ph.D. students for more than five years and it seemed that no one wanted a doctorate in humanities.

We write an abstract when ___________.( ) A: submitting articles to academic journals B: completing and submitting a Ph.D. dissertation or M.A. thesis C: submitting conference papers D: selecting which paper to read

PH值是溶液酸碱度的一种表示方法，（）时，溶液呈中性；（）时，溶液呈酸性；（）时，溶液呈碱性。 A: PH=7、PH>7、PH<7 B: PH=7、PH<7、PH>7 C: PH>7、PH=7、PH<7 D: PH<7、PH=7、PH>7

大多数病原菌生长的适宜pH值为() A: pH 5-6.8 B: PH 7.2-7.6 C: PH 8.2-8.6 D: PH 5-6 E: PH 7.6-7.8

校正酸度计用不到的PH缓冲溶液是（ ） A: PH=5.00 B: PH=4.00 C: PH=6.86 D: PH=9.18

玻璃pH值电极所测量pH值范围最好是（） A: pH小于1 B: pH=1-14 C: pH=1-9 D: pH大于9