问题
单项选择题
口角正常的位置在（）。
A.位于外眦垂直线上
B.位于内眦垂直线上
C.位于侧切牙与尖牙之间
D.位于尖牙与第一前磨牙之间
E.第一前磨牙与第二前磨牙之间
答案
参考答案：D
搜题请搜索小程序“爱下问搜题”
口角正常的位置在（）。
A.位于外眦垂直线上
B.位于内眦垂直线上
C.位于侧切牙与尖牙之间
D.位于尖牙与第一前磨牙之间
E.第一前磨牙与第二前磨牙之间
参考答案：D
| 阅读理解 | ||||||||||
| There are 3 basic types of rock climbing.Top roping is probably one of the most common types and the climber basically climbs with a partner.Top roping is a style in which a rope,used for the climber's safety,runs from a belayer(保护员)at the foot of a route through one or more carabiners(铁 锁)connected to an anchor system at the top of the route and back down to the climber,usually attaching to the climber by means of a harness.Assuming that the route is bottomtotop,the toprope climber generally will not fall more than a short distance and can thus safely attempt even the most difficult routes. The second type,which is very similar to top roping is called lead climbing.The buddy(同伴)system works the same way,one man on the ground belaying and the other climbing,but this time instead of the rope being at the top of the rock it has to be hooked into clasps(钩子)as the climber climbs up the rock. In both of these types of rock climbing the climbers has the luxury to sit off the rock face and rest on the rope.However,lead climbing requires the climber to hang from the rock face with one hand,grab the rope ,and pull it up to lip it into the clasps,and this can be very hard depending on many different things. The third type of rock climbing is called bouldering.Bouldering is a type of free climbing without any ropes or harnesses.The climber tends to stay much closer to the ground.This is the most demanding of all climbing.The climber must be able to complete the route without taking a rest on the rope.Often, during a bouldering route the climber is required to do a maneuver called dyno(动态动作). Dynos are basically launching yourself off the rock face,and then grabbing at a hold further away from you.This type of maneuver is where mental training plays a major role in climbing. Believe it or not,climbing is said to be about 75% legs and only 25% arms.To climb successfully one must use wonderful technique.One of the major rules of rock climbing is to always have 3 points touching the rock face.Whether it is both feet and one hand,or one foot and both hands,it is much easier to have your weight distributed on 3 points than it is 2.Another important concept to grasp is that your arms in most cases will not do the climbing；they only hold you into the rock face so that your legs are actually pushing you upward.The closer you are to the rock face,the easier it is to climb. Rock Climbing
| ||||||||||