求大神

不知道对不对，你可以参考一下。
Some studies suggest if the current set of proposed tariffs should come into force that is where China will turn to.

Some studies suggest that
(Brazil and Argentina)
is where China will turn to [import soybeans]
should (if) .....
结合上下文，就是这个意思:
“有些研究指出，一旦(美国)关税生效，中国会转向(巴西和阿根廷)进口大豆。”

A are B, and C suggest D.