Beijing took steps to limit the kinds of high-risk of borrowing money from the banks that can create the high price of housing, ______ happened in the United States．

A．a．as

B．that

C．how

D．while

“三级三场”式的编组站是（）排列的编组站。

A.三个车场呈横向

B.三个车场呈纵向

C.六个车场呈横向

D.六个车场呈纵向