It is suggested real-time bid ads help advertisers to______.
A．ease competition among themselves
B．lower their operational costs
C．hold a stable customer base
D．provide better online services

单项选择题一种社会制度是否先进和具有优越性，从根本上说是看其能否()。

未分类题'The critics'(Line 5, Para. 5)most probably refers to those on the side of______.A．President ObamaB．Supreme CourtC．Arizona state governmentD．Scholars in the research

未分类题In the second paragraph, the author discusses______.A．the overall economic picture of the publishing industryB．the paradoxical situation faced by scientific journalsC．the different outlooks of newspapers and scientific journalsD．the favorable economic situation for scientific publishers

未分类题It can be learned from Paragraph 4 that top journals______.A．value criticism from non-star scientistsB．cover the most important informationC．predominate people's choice of informationD．favor new and exciting studies

未分类题To show the desirable effects of immigration, the author makes use of______.A．illustrationB．comparisonC．explanationD．induction