【单选题】如右图,A、B是⊙O上的两点,AC是⊙O的切线,∠B=70°,则∠BAC等于
【简答题】单词拼写。 1. Going to Malaysia for further education for one month is a very e___________ and exciting experience for me. 2. It's good manners to show r ____________ for the elders. 3. He said that he r__...
【简答题】如图,MN为⊙O的直径,A、B是⊙O上的两点,过A作AC⊥MN于点C,过B作BD⊥MN于点D,P为DC上的任意一点,若MN=20,AC=8,BD=6,则PA+PB的最小值是______.
【判断题】尿素为白色或浅黄色的结晶体,吸湿性较强,易溶于水,水溶液呈碱性。()
【单选题】如图所示,A、B是⊙O上的两点,AC是⊙O的切线,∠B=65°,则∠BAC= [ ]
【简答题】如图,MN为⊙O的直径,A、B是⊙O上的两点,过A作AC⊥MN于点C,过B作BD⊥MN于点D,P为DC上的任意一点,若MN=20,AC=8,BD=6,则PA+PB的最小值是____.
【单选题】How did researchers know that ancient Greeks rushed to watch the Olympics?
A.
Thousands of people came to watch.
B.
The main stadium is still not big enough.
C.
They have found the related record of events.
D.
Many of them were visitors and pilgrims.
【单选题】如图,A、B是⊙O上的两点,AC是⊙O的切线,∠OBA=75°,⊙O的半径为1,则OC的长等于( )
【单选题】如图,A、B是⊙O上的两点,AC是⊙O的切线,∠B=70°,则∠BAC等于( )