They lost their way in the forest, and ___ made matters worse was that night began to fall.
A：it
B：which
C：that
D：what
关于“探究加速度与力、质量的关系”实验，下列说法中正确的是（ ）
下列函数中既是奇函数又是1,+∞上的增函数的是（ ）
