【单选题】( )是完成一定合格产品(工程实体或劳务)规定活动消耗的数量标准。
【判断题】人体细胞内的遗传物质发生突变所引起的一类疾病称为遗传病。
【单选题】They had camped once before, ____ they knew what to take.
【简答题】Before people knew how to make and use metals, engineering constructions were __ built of wood and stone.
【单选题】( )是完成一定合格产品(工程实体或劳务)规定活劳动消耗的数量标准。
【判断题】人体细胞内的遗传物质发生突变所引起的一类疾病称为遗传病。
【单选题】Before people knew how to make and use metals, engineering constructions were __________ built of wood or stone.
【判断题】接触某种化学物后体内不一定能检出该物质,但由该物质引起的机能改变却逐步积累起来,表现出中毒的病理征象,这种情况称为物质蓄积.