I started to write my own original sentences using the grammar I was learning.

题目

I started to write my own original sentences using the grammar I was learning.
这个句子中using前是不是省略了一个by
I was 前是不是省略了一个that?
by+doing 中的by能省吗
省略的怎会是that was?"that"代指什么？

答案

using the grammar (that) I was learning
是现在分词短语作状语.
I was 前是省略了一个that
using the grammar I was learning这个分词短语作状语,前不用加介词by.这是个现在分词短语,如果换成一个过去分词短语,比如used the grammar I was learning,比较下就会发现加介词by不合语法.
介词后面是跟动名词,而动名词只能作主、宾、表语.
今天有时间,虽然没分,但还是详细的跟你说说.