钳型电流表是一种不需断开电路就可以直接测量电路电流的便携式仪表。（）

单项选择题What is the difference between the second-generation IVF (Intracytoplasmic Sperm Injection) and the first-generation IVF-ET (in vitro fertilization-embryo transfer)? A、In vitro fertilization B、A single sperm is injected directly into an egg by a micromanipulation system in order to achieve fertilization. C、Preimplantation embryos are genetically tested for chromosomes or specific disease-causing genes D、Embryos need to be frozen

单项选择题使用数字万用表测量直流电压时，黑表笔应插入“V.Ω”插孔，红表笔插入“COM”插孔。（）