捕捉时，只取一条长约10米的细绳子，在绳头打好一个环扣后，准确地套在蟹洞口上。
O O O O O O B-Metric I-Metric O O B-Metric I-Metric I-Metric O B-Thing I-Thing I-Thing O O B-Thing I-Thing O O B-Metric I-Metric B-Thing I-Thing O O O O O O O B-Location I-Location I-Location O O