6. The worldwide race to develop an affordable synthetic fuel has so far consumed billions of dollars and __________ few results.
(A) yielded
(B) yielding
(C) yield ha
(D) has a yield of
7. Experiments in the photography of moving objects __________ in both the United States and Europe well before 1900.
(A) have been conducting
(B) were conducting
(C) had been conducted
(D) being conducted
8. The University of Georgia, __________ in 1785, was the first state supported university in the United States.
(A) chartered
(B) was chartered
(C) it was chartered
(D) to be chartered
9. Thanks to modern irrigation, crops now grow abundantly in areas where once __________ cacti and sagebrush could live.
(A) nor
(B) not the
(C) none other
(D) nothing but
10. __________, in the late 1800's, some libraries had to keep as many as twenty to thirty copies of each of Mary Jane Holmes's books on hand.
(A) Inventories showing
(B) That show inventories
(C) Inventories show that
(D) Showing the inventories
参考答案:
DCBBC BACAD