1 . Goals help students focus on their journey to a collection of achievements, meaning they make ________ most of their resources and time and can have motivation(动力)during times when they may feel like giving up. (用适当的词填空)

2 . My guide Zhaxi told me Tibetan antelopes suffered a lot in ________ 1980s and 1990s.(用适当的词填空)

3 . Some of our ancestors chose to subdue their fears and pursue _________ unknown —and this curiosity led them to, for instance, discover the use of fire. (用适当的词填空)