do you think it necessary for us to practise speaking english every day?前面的it指什么后面的Speaking为什么要加ing

do you think it necessary for us to practise speaking english every day?前面的it指什么后面的Speaking为什么要加ing
do you think it necessary for us to practise speaking english every day?前面的it指什么
后面的Speaking为什么要加ing

do you think it necessary for us to practise speaking english every day?前面的it指什么后面的Speaking为什么要加ing
首先 it necessary for us to practise speaking English 在句中成分 宾语从句
it 是形式宾语 真正的宾语是practise speaking English
it 指代的就是practise speaking English
而 speak 加ing 则是因为 practise 是动词 固定短语 practise doing sthing