题目

From deserts（沙漠）and beaches to playgrounds， we can find sand everywhere. But you might not know that sand is also useful.Sand is the second most-used things in the world after water， the BBC reported. However， the UN said we might be running out of it.Sand is made up of very small pieces of rock ， soil and minerals（矿物质）. It can take tens of thousands of years to form（形成）. But now we are using sand more quickly than it is being formed. According to the BBC， we use about 15 billion tons of sand every year to build houses， roads and other things. That 's enou在图所示的现象中，能用光的反射定律解释的是（ ）A．经凸透镜成放大的像B．山峦在水中的倒影C．在墙上投出的手影D．烛焰通过小孔成像