So suddenly that the animals in the zoo looked very frightened during the total solar eclipse (日全食)．
A. did the sky turn dark
B. the sky did turn dark
C. turned the sky dark
D. was the sky turned dark
网友回答
(答案→)A. did the sky turn dark
B. the sky did turn dark
C. turned the sky dark
D. was the sky turned dark
解析：句意：在日全食期间天空突然变黑了，以至于动物园里的动物都吓坏了。So …that放在句首时，so 后的句子应用部分倒装，故排除BC，天空变黑不能用被动，故排除D。故选A。