Singapore's public transport system(公共交通系统)is one of the best in the world, so you should have no problem finding your way around like a local. There are three main forms of public transport that you would find in any other major city--trains, buses and taxis.

TRAINS

    Trains run from 6: 00 am to midnight. Single trip tickets start at 80 cents. If you buy an EZ-link card for MYMI5, you can ride the trains and buses all you like.

    If you need more information, just call Transit Link on 1800 767 4333.

BUSES

    There are several bus services in Singapore and fares start at 80cents. Be sure to always ask the driver the cost of your ticket as he cannot give changes.

    If you need help, just call Transit Link on 1800 767 4333.

TAXIS

    There are three main taxi companies--city Cab(6552 2222), Comfort(6552 1111) and Tibs (6552 8888). Booking can also be made easily by calling the numbers listed above.

RENTAL CARS

    Driving in Singapore is a pleasure and if you like to travel at your own pace, renting a car is a good choice. Renting takes away the hassle of getting to places around Singapore. Just sit back and enjoy the city. It also means you'll get to see a lot more that a train or a bus won't let you see.

    For car rental, call Avis on +656737 1668

阅读下列材料，按要求完成后面提出的问题：

材料一：蝙蝠在黑暗中能自由地飞翔，用棉花住其耳朵，虽然把它放在明亮的房间里，仍像喝醉酒一样，一次一次地碰到障碍物，后来，物理学家证实了蝙蝠能发出①波，靠这种波的回声来确定目标和距离；

材料二：如果把八只同样的玻璃杯盛不同深度的水用一根细棒依次敲打杯子，可以发现声音的②和盛水量有关．如果调节适当，可演奏简单的乐谱，由此我们不难知道古代“编钟”的道理；

材料三：许多年前，“马可波罗”号帆船在“火地岛”失踪，经过多年的研究，揭开了“死亡之谜”，他们都是死于亚声，这是一种人耳听不到的声音，频率低于20Hz，而人的内脏的固有频率和亚声波极为相似，当二者相同时，会形成内脏的共振，严重时，把内脏振坏而丧生。

问题：

（1）请你将上面材料中①和②两处补上恰当的文字：① ____，② ____；

（2）从材料三中可以看出，声具有 ____。

卡片上分别画着三角形，平行四边形，梯形，正方形，长方形，要拿掉一张卡片，保证从剩下的卡片里面随机抽一样一定画着四边形，请问应该拿掉那张卡片?