2种减毒活疫苗如未同时接种,应至少间隔多少时间再接种()
A.2周
B.3周
C.4周
D.6周
参考答案:C
Beijing Man used fire for cooking food and also for light, warmth and ________
wild beasts.
A.protected from
B.protection from
C.protecting from
D.to protect from
人的皮肤从基底层向颗粒层表面移动所需要的时间是()天。