近年来，我国在航空航天领域取得了很多举世瞩目的成就，大大激发了同学们对太空物理问题的思考，下列说法中正确的是（　　）

    Sempoma is a wonderful place that photographers should never miss. The photos taken in Sempoma have ____ many big prizes in international photo competitions. It's a favourite place for those who take great ____ in photography around the world. People in Sempoma are not only friendly but also

____They are always glad to be your models (模特). People there are good at driving the boat ____the children. Life of the children in Sempoma is very simple. They have no homework to do because they do not ____ school. They have ____to worry about and they play ____every day in the water. If you ever go to Sempoma, make sure you find an experienced ____guide.

    He or she will lead you to all the fantastic sights.

某学校体育看台的侧面如图中阴影部分所示，看台有四级高度相等的小台阶，已知看台高为1.6米，现要做一个不锈钢的扶手AB及两根与FG垂直且长度均为0.8米的不锈钢架杆AD和BC（杆子的低端分别为D、C），且∠DAB=66.5°（cos66.5°≈0.4）．

（1）求点D与点C的高度差DH；

（2）求所用不锈钢材料的总长度l（即AD+AB+BC的长）．

如图所示，当开关S闭合后，灯泡L₁、L₂均正常发光，但过一会儿，两灯均突然熄灭．某同学利用电压表探究电路故障，他用电压表分别接到灯L₁、灯L₂两端测量电压，发现灯L₁两端电压为零，灯L₂两端电压不为零，由此可判断电路的故障是（  ）