如图，已知 ΔABC 中， AB = AC ， BD 、 CE 是高， BD 与 CE 相交于点 O
（1）求证： OB = OC ；
（2）若 ∠ ABC = 50 ° ，求 ∠ BOC 的度数．
28．--- What do you think of your winning the game? --- On the one hand, I am proud of it; but on the other hand, I feel I it better.
--- Can I use the telephone on the table, sir? --- Under no circumstances the telephone in the office for personal affairs.
--- Is Bob still working in your school? --- I’m afraid not. He is said and in a private school recently.
There’s nobody here our English teacher. Fortunately, she is more than glad to give us help when we are in trouble.
--- What does the notice on the wall say? --- ‘No person take books out of the reading room; otherwise he would be fined.’
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