frightened ['fraɪtnd]

adj. 害怕的;受惊的; v. （使）惊恐( frighten的过去式和过去分词);吓唬;

💡 fright惊恐+en表动词 + ed...的→ 受惊的, 受恐吓的

"Survivors waited for the rescue boats, dazed and frightened."

近义：appalled, apprehensive, petrified, awed, awestricken, awestruck

flood [flʌd] 词频1 词根: 流动

n. 洪水;泛滥;溢流;探照灯; vi. 涌出;为水淹没; vt. 淹没;

💡 flo(flow)+od(名词后缀)→泛滥；洪水

"They built dykes and dam to hold back the rising flood waters."

近义：inundate, overflow, submerge, swamp, deluge, drown 反义：purge, rinse, sap, scoop, swill, bleed

become [bɪ'kʌm] 词频1

vi. 变为，成为;变得;变成; vt. 适合，适宜;相称，相当;变成;发生;

💡 be(upon)+come→变为；成为(=to come upon）

"In a world that had suddenly become alien and dangerous, he was her only security."

近义：turn, wax, get, go, grow, suit 反义：remain, keep, stay, get

must [mʌst] 词频1

aux. 必须;必然要;（做出逻辑推断）;（表示坚持）; n. 必须做的事，必不可少的事物;葡萄汁;霉臭;麝香; vt.& vi. （表示必要或很重要）必须;（提出建议）应该;得;（表示很可能或符合逻辑）一定; adj. 不可或缺的;狂暴的;

"You must be able to speak French for this job."

近义：ought, should, necessaries, necessity, precondition, prerequisite

unduly ['ʌn'dju:li]

adv. 不适当地;过分地;过度地;不相称地;

"He did not sound unduly worried at the prospect."

近义：immoderately, incorrectly, inordinately, overly, overmuch, excessively 反义：incompletely, approximately, insufficiently, miserably, nearly, poorly