At that time she was the first woman ever____a lecture in publicA to give B.to have given为什么不用to have given?不是强调give在be the first woman之前吗?两个动作又不是很紧凑的.

At that time she was the first woman ever____a lecture in publicA to give B.to have given为什么不用to have given?不是强调give在be the first woman之前吗?两个动作又不是很紧凑的.
At that time she was the first woman ever____a lecture in public
A to give B.to have given
为什么不用to have given?不是强调give在be the first woman之前吗?
两个动作又不是很紧凑的.

At that time she was the first woman ever____a lecture in publicA to give B.to have given为什么不用to have given?不是强调give在be the first woman之前吗?两个动作又不是很紧凑的.
因为完成时不与过去具体的时间连用
At that time 有了,所以不能用have given
句子的意思是讲座是那个女人给的,所以用主动.

不定式做定语,强调这个动作发生在was之后,也就是过去的将来动作意思是 说,她是第一个将要公开演讲的女士

在这里give和be the first woman不是两个动作，句子的意思是强调她是第一个作公众演讲的女人，to give 用来修饰woman.