原子序数依次增大的四种短周期元素A、B、C、D，其中A与D同主族，B与C同周期，A、D原子的最外层电子数都是1，B原子最外层电子数是次外层电子数的2倍，C原子最外层电子数比B原子多2个。A、C单质在常温下均为气体，它们在点燃下以体积比2∶1完全反应，生成物在常温下是液体。此液体与D单质能激烈反应生成A的单质，所得溶液滴入酚酞显红色，同时溶液中含有与氖原子的电子层结构相同的两种离子。回答下列问题：

⑴、写出BC₂的电子式 ______ ，结构式 ______ 。

⑵、A、C、D元素形成的化合物中含有的化学键的类型为____  ，该物质的晶体类型是 __ 。

⑶、写出一种由A、B、C、D四种元素共同组成的化合物的化学式 ____ 。

语法填空

     Daisy had always longed to help 1(danger)_______ species of wildlife. One day she woke up and

found a 2(fly)____ carpet by her bed. "Where do you want to go ?" it asked. Daisy responded 3

(immediate)________. "I'd like to see some rare wildlife." she said. "Please take me to a distant land

4______I can find the animal 5____ gave fur to make this sweater."

At once the carpet flew away and took her to Tibet. There Daisy saw an antelope 6(look)______ sad.

It said,"We 7(kill)_________ for the wool beneath our stomachs. Our fur is being used to make

sweaters for people like you. As a result, we are now a rare species. 8____ that Daisy cried, "I'm sorry

I 9(not know)_____that. I wonder 10____ is being done to help you .