题目

Feeding birds is a popular way to watch wildlife.But experts say it might put wild birds at risk.Feeding birds is not necessary for their survival except in extreme weather conditions.Feeders(喂食器)can definitely help birds get through that kind of weather.But most birds eat insects and show little interest in bird feeders.For those birds，we can grow native plants in a natural environment.Birds which are fond of eating seeds will be more likely to come to feeders if there is some cover nearby.This lets them feed and then fly to protective areas，such as in trees.The most common mistake 广州正佳广场甲、乙、丙三架观光电梯，甲中乘客看一高楼在向下运动；乙中乘客看甲在向下运动；丙中乘客看甲、乙都在向上运动。这三架电梯相对地面的运动情况可能是（　　）A．甲向上、乙向下、丙不动B．甲向上、乙向上、丙向下C．甲向上、乙向上、丙不动D．甲向上、乙向上、丙也向上，但比甲、乙都慢