下列词语中，划线字的注音全都正确的一项是（    ）

拼读练习，写出声母与韵母ai四声的拼读音节。

g  + ai____ ____ ____ ____

k + ai____ ____ ____ ____

h + ai____ ____ ____ ____

阅读下面的短文，将划线部分的句子译成汉语或英语。
   My name is Bob. I live in Toronto, Canada.I want a pen pal in China.I think China is a very interesting country. I'm 14 years old and my birthday is in November. 我会说英语. I also know a little French. I have a brother. Paul, and a sister. Sarah. They have pen pals in the United Kingdom and Australia.I like going to the movies with my friends and playing sports. 我最喜欢的科目是体育.It’s fun. But I don't like math. It's too difficult!

已知平面α∥平面β，P是α，β外一点，过点P的直线m与α，β分别交于点A，C，过点P的直线n与α，β分别交于点B，D，且PA＝6，AC＝9，PD＝8，则BD的长为(　　)