Grandma______asleep when she _____the TV play last night .A was falling ,was watching B was falling,watched C fell,watched D fell,was watching 请帮忙选择一下,并加以分析,谢谢了

Grandma______asleep when she _____the TV play last night .A was falling ,was watching B was falling,watched C fell,watched D fell,was watching 请帮忙选择一下,并加以分析,谢谢了
Grandma______asleep when she _____the TV play last night .
A was falling ,was watching B was falling,watched C fell,
watched D fell,was watching
请帮忙选择一下,并加以分析,谢谢了

Grandma______asleep when she _____the TV play last night .A was falling ,was watching B was falling,watched C fell,watched D fell,was watching 请帮忙选择一下,并加以分析,谢谢了
D
奶奶昨晚在看电视的时候睡着了
在看电视：过去进行时
睡着了：一般过去时
比如错误的：奶奶昨晚在看电视的时候正在睡觉
都用过去进行时,显然逻辑不通,

D
when的一种用法,表示"当....发生了...."
"昨晚奶奶看电视时睡着了"