36. Bufo marinus toads, fierce predators that will eat frogs, lizards, and even small birds, are native to South America but were introduced into Florida during the 1930's in an attempt to control pests in the state's vast sugarcane fields.
(A) are native to South America but were introduced into Florida during the 1930's in an attempt to control (B) are native in South America but were introduced into Florida during the 1930's as attempts to control (C) are natives of South America but were introduced into Florida during the 1930's in an attempt at controlling (D) had been native to South America but were introduced to Florida during the 1930's as an attempt at controlling (E) had been natives of South America but were introduced to Florida during the 1930's as attempts at controlling
C中的at controlling有这种用法吗？如果把C 中的of 改成to是不是就可以选C了？ | 
