请问这两道英语选择题是考察哪部分语法知识的?总是错,想复习一下语法点了.

请问这两道英语选择题是考察哪部分语法知识的?总是错,想复习一下语法点了.
.It is not uncommon for ________ problems of communication between old and young.
A.there to be
B.there being
C.there to being
D.there be
It is with her support _____he won the Nobel Prize.
A.which
B.that
C.what
D.when