You can borrow an umbrella if you need (one).という文で、( )が、this だと何故ダメなのでしょうか?…①
This rose does not smell as sweet as ( )I bought the other day.という文で、( )がsuch,whichだとなぜ不適なのでしょうか….➁
The earthquake was the biggest (one) that we had ever experienced.という文で
( )がallだとなぜダメなのですか?…③