Experiments in the photography of moving objects______in both the United States

游客2024-08-21 12

问题 Experiments in the photography of moving objects______in both the United States and Europe well before 1900.

选项 A、were conducting
B、have been conducting
C、had been conducted
D、had conducted

答案 C

解析由后面的时间可知应填过去时态，而“before+时间”通常与完成时连用。

转载请注明原文地址:https://tihaiku.com/zcyy/3729137.html

相关试题推荐

随机试题

最新回复(0)

TheUnitedStateshaslongbeenknownasanationofimmigrantsbecausemanyof