下列群落演替系列中，哪一种演替属于初生演替(    )

《归去来兮辞》一诗中写为什么整天心神不定还想去什么地方的句子____ ？

用所给词的适当形式填空

①—Where is Mr. Green?

—He ____ (go) to Beijing on business.

②You mustn't swim in the lake. Look at the sign “No ____ (swim). ”

③ After school, he always finishes ____ (do) his homework first.

④ My sister ____ (arrive) at the airport in two hours.

⑤ David is coming to visit us. I’m looking forward to ____ (meet) him.