Their first problem was crossing over a huge mountain.

VOA: special.2009.02.11

The hymn doesn't anywhere refer to people crossing over on dry land.

在赞美诗中并没有提到人们从地面上穿过海洋。

耶鲁公开课 - 旧约导论课程节选

Following a transformation the study of which is not the concern of the social sciences but rather of biology and psychology, a crossing over came about from a stage where nothing had a meaning to another where everything possessed it.

这门学科并不属社会科学的范畴,而是属于生物学，心理学，此种转变是一种跨越，从一个什么都没有意义的时代到,一个每样东西都能表达的时代的。

耶鲁公开课 - 文学理论导论课程节选

So that crossing point actually occurs at a - c over 3b.

因此交点确实是/3b

耶鲁公开课 - 博弈论课程节选