[求助]几道语法真题求助

tigercsh

有几道真题不知道答案的原因,想请教高手指点,多谢:

200308

39.   Communal dance, as a powerful symbol of mutual regard and cooperation group, underlies

                                      A                                      B                      C

enduring traditions in folk dancing.

答案C, 不知道应如何改,觉得B也有点问题

200205

39. Due to persistent inbreeding, self-pollinating plants have genetically more uniform

A                                          B

than cross-pollinated plants,which harbor more genetic variability.

C                     D

答案B,不知道错在哪里

200208

7. ______ land and money enabled construction of the Union Pacific railroad to begin from Council Bluffs, Iowa , in 1865.

(A) By the government granting of

(B) Government grants of

(C) For the government to grant

(D) Government grants so that

答案B,不清楚句子结构是如何

8. Appointments to the United States Supreme Court and all lower federal courts ____ be the President with the advice and consent of the Senate.

(A) making

(B) to make

(C) are made

(D) have made

答案C,同样无法理解句式

200209

16.   An activist for women's rights, Leonora O'Reilly promoted women's vocational training

           A

besides fought for increased wages for garment workers.

   B               C      D

答案C,  俺选的是B

13. In geometry, an ellipse may be defined as the locus of all points -------distances from two fixed points is constant.  

(A) which as the sum of  

(B) of the sum which

(C) whose sum of whose  

(D) whose sum that the  

答案B, 不懂句型

请高手指点迷津!万分感谢.