重点讲解：
1. depend on 取决（于）；有赖（于）；
例句：The outcome will depend on how well we perform.
结果将依我们表现的好坏而定!_8bK,*-joEio9J。
2. have to do sth. 需要；必须；不得不；
例句：Sometimes things have to fall apart to make way for better things.
有时候要到达谷底，才会慢慢变好OS3ynvfD^WcF&_。
3. check in 检查；
例句：The final step is to check in with the solution's progress and determine if it is still the right one.
最后一步就是检查方案执行的过程，确定它是否仍然正确mmXowDev6a1DwkB。