Question

20．这些志愿者在运动会前接受培训是很有必要的．It's necessary for these volunteers to receive training before the sports meeting．．

Answer 1

分析 It's necessary for these volunteers to receive training before the sports meeting．

解答 答案：It's necessary for these volunteers to receive training before the sports meeting．这里是表示对某人来说做某事是怎么样的用句型it is+adj+for sb+to do sth，it是这个句子的形式主语，真正的主语是to do sth．必要的形容词necessary，这些志愿者these volunteers，接受培训receive training，故It's necessary for these volunteers to receive training，加上时间状语在运动会前 before the sports meeting．故答案是It's necessary for these volunteers to receive training before the sports meeting．

点评 本题要注意It is adj+for sb to do sth与 It is adj+of sb to do sth的各自的用法区别是
1）for sb．常用于表示事物的特征特点，表示客观形式的形容词，如easy，hard，difficult，interesting，impossible等：
　　 It's very hard for him to study two languages．对他来说学两门外语是很难的．
2）of sb的句型一般用表示人物的性格，品德，表示主观感情或态度的形容词，如good，kind，nice，clever，foolish，right．
　　 It's very nice of you to help me．你来帮助我，你真是太好了．