Hxen.com's tips：Every day persisted can learn English well!-->■Learn English Everyday■
depend on依赖,依靠;取决于,随…而定
例句：They depend on a particular historical situation.
它们取决于特定的历史境况。
It all depends on [upon] the weather.
那完全得看天气如何而定。
make a promise答应,许诺,允诺,保证
例句：He made a solemn promise to do better.
他郑重保证要做得更好。
2.Caster Semenya led from the start and won the race by a large margin.
won the race by a large margin以绝对优势获得胜利，相当于win overwhemlingly
3.The attack happened despite heightened security ahead of the vote which the Taliban have vowed to disrupt.
ahead of领先于…,在…之前,超过…,提前…
例句：She was always well ahead of the rest of the class.
她在班上总是遥遥领先.
We determine to fulfill the task ahead of time.
我们决定提前完成任务。
4.It was started when someone let off a firework, but hundreds of people were trapped inside the building because the fire doors had been locked.
let off放出,饶恕,准许...暂停工作
例句：The boys were itching to let off their fireworks.
男孩子们急着想放烟火。