Some Maths problems in this book are dif
问题:
Some Maths problems in this book are difficult for the students work out.[ ]
A. so, that
B. not, but
C. such, that
D. too, to
Some Maths problems in this book are difficult for the students work out.[ ]
A. so, that
B. not, but
C. such, that
D. too, to