解释下列词语

①洋溢：                                                             

②伶俐：                                                            

③恐吓：                                                            

④径自：                                                            

⑤无精打采：                                                            

⑥异想天开：                                                            

⑦无缘无故：                                                            

在构筑密闭墙时，一般应先构筑回风侧密闭墙，后构筑进风侧密闭墙。（）