Some Math problems are difficult for the students work out.A. so, thatB. not, butC. such,

Some Math problems are difficult for the students work out.
A. so, that
B. not, but
C. such, that
D. too, to

A. so, thatB. not, butC. such, that(答案→)D. too, to解析：句意：一些数学难题对于学生太难而算不出来。so…that such…that ,如此……以至于……。that后加从句。not,but。不是……而是。too,to太……而不做……。根据句意，故选D。

收益了