每日一词学英语(81): imponderable

英国的猪流感愈演愈烈，未来几个月可能会死6.5万人。（From Guardian, 16 July 2009, Swine flu: Stark figures hide imponderables）

There are too many imponderables: whether or not the nature of the virus changes, the level of accumulated resistance in the population, whether seasonal changes lead to an upsurge in levels of illness from the virus, and whether school closures over the summer holidays reduce the level of acceleration in the disease. 太多事情不可估量：病毒是否变质？大众对猪流感的抵抗水平，季节改变的影响，学校放暑假能否减少疾病传播？

Noun [usually pl.] (formal) something that is difficult to measure or estimate. 无法估量的事物。
*We can’t predict the outcome. There are too many imponderables.