根据短文内容，判断正误。

      When you're invited to have dinner at a foreigner's home, please remember the followings.

      At the table, when the hostess(女主人) picks up her napkin, you may pick up yours and put it on your legs.

      If a servant(佣人) passes food around, he will pass the dish to you at your left hand so that you can easily serve yourself with your right hand. Never serve yourself while the dish is on your right. It is then the turn of your neighbour on the right.

      Do not reach across the table to get something in front of someone. That is not polite. Ask him or her to pass it to you.

      There are things in the middle of the table, such as bread, butter, and candies. You shouldn’t take any until the hostess tells the servant to pass them to you.

      Do not leave your seat without saying anything. If you need to leave the table to go to the washroom or do something else, you should say “Excuse me for a moment, please.”

如图是放在水平地面上的一把椅子的侧面图，椅子高为AC，椅面宽为BE，椅脚高为ED，且AC⊥BE，AC⊥CD，AC∥ED．从点A测得点D、E的俯角分别为64°和53°．已知ED=35cm，求椅子高AC约为多少？

（参考数据：tan53°≈ $\frac{4}{3}$ ，sin53°≈ $\frac{4}{5}$ ，tan64°≈2，sin64°≈ $\frac{9}{10}$ ）

步骤一：取适量待测液，加入NaOH溶液并加热，得到溶液A，并产生刺激性气味的气体

步骤二：向溶液A加入足量稀盐酸和BaCl₂溶液，得到溶液B、白色沉淀和有刺激性气味的气体

步骤三：往B溶液中通入适量Cl₂，得到黄褐色溶液C

1963年，周恩来总理将对台政策归纳为“一纲四目”。“一纲”是指台湾必须回到祖国的怀抱。“四目”则是具体的操作方案：台湾回归祖国后，除外交必须统一于中央外，当地军政大权、人事安排等“悉委于”蒋介石，由蒋介石安排等。该政策（    ）

读“东北部分城市降雪初日期、降雪终日期和最大积雪厚度的分布图”，完成以下问题