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a. 不寻常的, 罕见的, 与众不同的
adj.
不常见的; 难得的 稀罕的 例外的; 奇异的

It is quite unusual for a freshman to be younger than eighteen or older than nineteen.

unusual loss unusual beat unusual service conditions unusual casualty reserve unusual deformation unusual increase unusual character unusual structure unusual epilepsy unusual base unusual child unusual facies unusual plant unusual weather unusual drought unusual loss　unusual beat　unusual service conditions　unusual casualty reserve　unusual deformation　unusual increase　unusual character　unusual structure　unusual epilepsy　unusual base　unusual child　unusual facies　unusual plant　unusual weather　unusual drought