请问staudy的现在分词 drop的现在分词valley的复数形式windy的名词形式?

问题描述:

请问staudy的现在分词 drop的现在分词valley的复数形式windy的名词形式?
It is necessary for me to take a taxi.中it is necessary for me可以被那些词或词组替换?
可否写成:I had better take a taxi.

第一个是study 的现在分词吧 studying
后面的分别是dropping valleys wind
最后一个可以是 I must,I have to,I need,or It is required for me