题干
I was really scared and I didn't know ___________ when I saw a snake that day.
A：how to do
B：when to do
C：where to do
D：what to do
答案(点此获取答案解析）
D
I was really scared and I didn't know ___________ when I saw a snake that day.
A：how to do
B：when to do
C：where to do
D：what to do
