求教关于x will happen if y happens句型～～谢谢指点啊

经常在OG里面看见类似于这个题目的句型，他说“x will happen if y happens” 请问这个句型跟虚拟语气的关系是什么？？

然后后面我再加一个题目是GWD12- 3的 想请各位NN帮忙看一下 这两个是一回事儿么？还是一个是虚拟一个是那个IF从句啊？真心求教～～～～

OG.While some
academicians believe that business ethics should be integrated into every
business course, others say that students will take ethics seriously only if
it would be taught as a separately required course.

(A)
only if it would be taught as a separately required course

(B)
only if it is taught as a separate, required course

(C)
if it is taught only as a course required separately

(D)
if it was taught only as a separate and required course（B）

(E)
if it would only be taught as a required course, separately

GWD-12-Q3:

Were it not for the
fusion-powered heat and radiation that rush from its core, instead its own
weight would cause a star to collapse.

A.    
instead its own weight would cause a star to collapse

B.     
instead a star would have collapsed under its own weight

C.    
a star would have to be collapsing under its own weight

D.    
a star would collapse under its own weight

E.     
its own weight would have caused a star’s collapse