塑限的含义是指（）。
参考答案：土体由半固体状态向可塑性状态过渡的界限含水量
If we had taken such effective ______ much earlier, the river would not be polluted so seriously now.
A．treasures
B．efforts
C．measures
D．actions
花卉盆栽时，选择与准备花盆要注意哪些问题？
