问答题

共用题干题

下面片段选自某高中英语课堂教学实录。
T：Good morning，boys and girls.We talked about some verbs yesterday.Now I´d like to see whether you have learned to use them.Are you ready？
Ss ：Yes.
T：Listen!Yesterday，you were going to play football after school when it began to rain，so you tidn´t do it.Can you describe it with the word "prevent"？Who would like to have a try？
S1：We didn´t play football yesterday because a sudden rain prevented us.
T：OK.But would you please begin your sentence with "The sudden rain..."？Who´d like to try？
S2：The sudden rain prevented us to play football yesterday.
T：Oh，you are so quick，and you are almost right.Do we say "prevent somebody to do something"or "prevent somebody..."
S3：Oh.The sudden rain prevented us from playing football yesterday.
T：Prefect.Let´s read S3´s sentence together and remember the verb pattern of “prevent”，OK？
根据该教学片段回答下面四个问题：

当该教师发现学生没有完全掌握所学内容时，采取了什么补救方法？