Signed tree
[計] 符號表示的樹
?? 詞語組成解析
signed
[saind]
adj. 有符號的，有正負之分的;
tree
[tri]
n. 樹;木料;樹狀圖;宗譜;
vt. 把…趕上樹;使處于困境;把鞋型插入（鞋內）;
??? 情景例句
When you learn a new verb, learn its various forms.
學到了新動詞時，記住它的各種形式。
Counsel must be followed, not praised.
忠告必須照辦，而不是贊美。
At last I hung up the receiver.
我終于掛上了話筒。