________ your letter, I would have started off two days ago.

A．If I received

B．Should I receive

C．If I could have received

D．Had I received

如图所示，一圆柱形容器，底面积为100cm²，内装有20cm深的水．现把一质量为120g，密度为0.6×10³kg/m³的木块放入水中，水未溢出杯外．（计算时ρ_水取1.0×10³kg/m³，ρ_铁取8.0×10³kg/m³，g取10N/kg）求：

（1）静止后木块浸入水中的体积．

（2）若把木块缓慢地刚好全部压入水中（水未溢出），此时水对容器底的压强为多大？

（3）若在木块上放一铁块，使他们不沉入水底，铁块的最大质量是多少？