a. 不可预知的
There's unpredictable weather, changes in soil quality, and the ever-present possibility that pests and diseases may pay a visit.
六级 · CET-6 2020年12月 第1套 · Part III 第36–45题
First, the number of students would be unpredictable.
六级 · CET-6 2020年12月 第3套 · Part III 第36–45题
Ever since humanity began to farm our own food, we've faced the unpredictable rain that is both friend and enemy.
六级 · CET-6 2018年6月 第2套 · Part III 第36–45题
Biologist Jill Farrant of the University of Cape Town in South Africa says that nature has plenty of answers for people who want to grow crops in places with unpredictable rainfall.
六级 · CET-6 2018年6月 第2套 · Part III 第36–45题