根据句意及首字母提示补全单词或词组。

①He wants to ____ (训练)his worker for the work.

②I am not sure.____ (也许)you are right.

③.Smoking is bad for our ____(健康).

④Many of us have ____ (听说)the film Walking with Dinosaurs (《与恐龙同行》) ,but no one has seen it.

⑤His parents want him to____ (退学)and help them work on the farm.