46. Because of a _____ engagement, Lora couldn’t attend my birthday party last Saturday.
A. pioneer B. premature C. prior D. past
47. No new investments or acquisitions will be made without the _______ of Kolsen Reconds’ board of directors.
A. convenience B. adoption C. sanction D. event
48. ______ much is known about what occurs during sleep, the precise function of sleep and its different stages remains largely in the realm of assumption.
A. Because B. For C. Since D. While
49. The glass vessels should be handled most carefully since they are ______.
A. intricate B. fragile C. subtle D. crisp
50. Hill slopes are cleared of forests to make way for crops, but this only ______ the crisis.
A. accelerates B. prevails C. ascends D. precedes
46.【答案】C。解析：考查詞義辨析。句意：因?yàn)榱碛邪才旁谙龋现芰鵏ora沒能參加我的生日晚會(huì)。pioneer (n.) 先驅(qū)者，創(chuàng)始人，開拓者；premature不成熟的；prior優(yōu)先的，在前的，符合句意；past過去的。故答案選C。
47.【答案】C。解析：考查名詞辨析。句意：沒有Kolsen Records董事會(huì)的批準(zhǔn)，不能進(jìn)行新的投資及收購。convenience方便；adoption采用，采納；sanction制裁；批準(zhǔn)；event事件。結(jié)合句意可知應(yīng)選C。
48.【答案】D。解析：考查讓步狀語從句。句意：關(guān)于睡眠過程人們雖然了解很多，但是關(guān)于睡眠的確切功能和各個(gè)不同階段，人們還不是很清楚。根據(jù)句意可知，前后為轉(zhuǎn)折讓步的邏輯關(guān)系。because表原因（引導(dǎo)原因狀語從句）；for因?yàn)椋ǔＳ米鞑⒘羞B詞）；since既然（引導(dǎo)原因狀語從句），自……以來（引導(dǎo)時(shí)間狀語從句）；while雖然（引導(dǎo)讓步狀語從句），當(dāng)……的時(shí)候（引導(dǎo)時(shí)間狀語從句）。
49.【答案】B。解析：考查形容詞辨析。句意：處理這種玻璃容器的時(shí)候要最為小心，因?yàn)樗鼈兒苋菀姿椤ntricate意為“錯(cuò)綜復(fù)雜的，復(fù)雜精細(xì)的”，與complicated同義；fragile意為“易碎的，脆的；虛弱的，脆弱的”；subtle意為“微妙的；精細(xì)的；敏感的”；crisp意為“脆的，(果蔬等)鮮脆的”。結(jié)合語境，這里是指玻璃易碎，故答案為B。
50.【答案】A。解析：考查動(dòng)詞辨析。句意：清除山坡上的森林以騰出土地來種植莊稼，但這只是加速了生態(tài)危機(jī)。accelerate加快，促進(jìn)；prevail流行，盛行，戰(zhàn)勝；ascend上升，升高；precede在……之前，先于……。結(jié)合語境，正確答案為A。
