heavy section prop

例句：

1. 1. The heavy section of the machine isprone to wear and tear.
   机器的重型部分容易磨损。
2. 2. The heavy section of thebridge needs to be reinforced.
   桥梁的重型部分需要加固。
3. 3. The heavy section ofthe building is causing structural problems.
   建筑的重型部分导致了结构问题。