根据句意和空缺处所给首字母写单词。
____ I have m________hobbies, such as swimming, rowing and hiking.
____ He said he would never f_________ the trip to Mount Fanjin.
____ We should do more exercise to keep h ________.
____ Tongren have developed r          into a modern city in the recent years.
____ My little sister is so young that she can't look after h________.

如图所示，七块完全相同的砖块按照图示的方式叠放起来，每块砖的长度均为L，为保证砖块不倒下，6号砖块与7号砖块之间的距离S将不超过（　　）