77． Shanghai is so big that we can get lost ____________(容易地)in it．

76． Miss Lu is often __________ (邀请) to give us talks on teenagers’ education．

75． －Can you　 ___________(描绘)the attacker to the police ? －He is tall and strong．

74． If we keep _________ (砍伐)down the trees, wild animals will have nowhere to live．

73． I think it’s our_________(职责) to protect the environment．

72． Why not sing the song with your mouth fully ________ (张开)．

A． 根据句意、汉语或首字母提示写出单词。

71． Do you know the saying, “A friend in need is a friend ________(真正地)?”