a semiautomatic rifle的用法和样例：
- Canadian, John Garand invented the M1 semiautomatic rifle in 1934.
- The guard was killed with a high-powered rifle.
- Get a rifle that shoots straight.
- The 3,4-dihydroxyphenylalanine reaction was used to determine melanocyte content, and a semiautomatic image analysis system calculated the percentage of repigmentation.