Only by ____your attention on what you're learning can you learn it well.A focusing B paying 选A
问题描述：
Only by ____your attention on what you're learning can you learn it well.A focusing B paying 选A
为什么
答
A.
这里面是两个固定短语,
pay attention to
focus attention on
再加上by是一个介词,后面要加动词的ing形式.