温度为0℃，纬度为45°的每平方厘米的海平面上所承受的压力为（） ["0.4MPa","0.2MPa","0.13MPa","0.3MPa","标准大气压"]
患儿，男，4岁。智能落后，表情呆滞，鼻梁低，舌宽大并常伸出口外，皮肤苍黄、粗糙。首选哪项检查（） ["染色体核型分析","尿筛查","甲状腺功能","尿有机酸分析","头颅CT"]
OTDR测试接头损耗是用（）。 ["2PA","LSA的五点法","剪断法","插入法"]
水下30m深处的压力相当于（） ["0.4MPa","0.2MPa","0.13MPa","0.3MPa","标准大气压"]
下列不是开关量信号的是（）。 ["电压信号","电流信号","光电开关","温度信号","接近开关","压力信号"]
简述增加肉嫩度的方法。
