講解：
amass sth
(尤指大量)積累,積聚
He amassed a fortune from silver mining.
他靠開采銀礦積累了一筆財(cái)富。

a level playing field
人人機(jī)會(huì)均等
The sports game should keep a level playing field.
體育比賽應(yīng)該保證人人機(jī)會(huì)均等。

be on trial
受審
(法院的)審訊,審理,審判:
He's on trial for murder.
他因涉嫌謀殺罪而受審。

under threat
兇兆；征兆:
These ancient woodlands are under threat from new road developments.
新道路的發(fā)展可能對(duì)這些古老的林地造成破壞。

hold sb / sth back
妨礙進(jìn)展:
Do you think that mixed-ability classes hold back the better students?
你認(rèn)為把不同能力的學(xué)生混合在一起的班級(jí)會(huì)妨礙較高水平學(xué)生的進(jìn)步嗎？

at the cost of
(為做某事涉及的)努力,代價(jià),損失:
She saved him from the fire but at the cost of her own life (= she died).
她從火中把他救了出來,卻犧牲了自己的生命。