a constitutional amendment的用法和样例：
- Reactionary forces in the Senate would not allow a constitutional amendment for direct election of senators to pass.
- But Mr Topi is expected to push for a constitutional amendment to set a time limit.
- Germany, for instance, recently passed a constitutional amendment to limit the build-up of debt.
- A constitutional amendment approved in 1969 limits presidents and deputies to one term, although a deputy may run again for an Assembly seat after sitting out a term.
- Britain is a constitutional monarchy.