fall through
1．descend accidentally through掉进
The boy fell through the ice and was drowned.这个男孩掉入冰水中淹死了。
2．fail to be completed，fail to occur失败；不执行；落空
If your new agreement falls through，the workers in your company will go on strike．如果你们的新协议不落实，贵公司的工人就要罢工了。
I hope the plan doesn't fall through a second time owing to lack of funds．我不希望这项计划因缺少资金再次落空。
We are going on a picnic tomorrow，unless it falls through because of the weather．我们明天要去野餐，除非天气不好去不成。