Ostriches(鸵鸟) have been said to be so stupid that they react to danger by burying their heads in sand. This belief caused the popular phrases to be born: play the ostrich. It’s often used to describe people 小题1:________ refuse to face painful facts. They prefer to ignore the truth. It is like children sticking their fingers in the ears 小题2:________ crying, “I can’t hear you!”

But do ostriches really bury their heads in sand when they are in danger? The answer is no for sure! 小题3:_______ ostriches are flightless(不会飞的) birds, they can run as fast as 40 miles per hour. So, if they find 小题4:_______ in danger, they will run very fast.

It’s a false statement we’ve thought of as 小题5:________ truth for long. So, how did the phrase “play the ostrich” come from? Well,小题6:______ fact, ostriches swallow sand and pebbles(鹅卵石) to help grind(磨碎) food in their stomachs. This means they have to bend 小题7:_______ and put their heads into sand to collect pebbles. That’s 小题8:_______ a false statement was born

（12分）在练习使用多用表的实验中

（1）某同学连接的电路如图所示

①若旋转选择开关，使尖端对准直流电流挡，此时测得的是通过________的电流；（填R₁或R₂）

②若断开电路中的电键，旋转选择开关使其尖端对准欧姆挡，此时测得的是________的电阻；（填R₁、R₂、R₁和R₂串联或R₁和R₂并联）

③若旋转选择开关，使尖端对准直流电压挡，闭合电键，并将滑动变阻器的滑片移至最左端，此时测得的是________两端的电压。（填R₁或R₂）

（2）（单选）在使用多用表的欧姆挡测量电阻时，若（ ）

A．双手捏住两表笔金属杆，测量值将偏大

B．测量时发现指针偏离中央刻度过大，则必需减小倍率，重新调零后再进行测量

C．选择“´10”倍率测量时发现指针位于20与30正中间，则测量值小于25W

D．欧姆表内的电池使用时间太长，虽然完成调零，但测量值将略偏大