virological surveillance began in 2000 and sentinel surveillance was established at six hospitals in 2001.
该国2000年开始实施病毒学监测,2001年在六家医院确立了哨点监测制度。
at six months, caregivers should introduce foods in small amounts and gradually increase the quantity as the child gets older.
在六个月时,护理人员应开始少量添加补充食品,并随着婴儿的成长,逐渐增加喂养量。
at six feet tall, the eastern sarus crane is the world’s tallest flying bird.
赤颈鹤足有六英尺高,是世界上身材最高的飞禽。
when tested at six months, only three of the infants were infected, compared to the 50 that would likely have been infected had they not received the antiretroviral.