—Does Jim come from _______?
—Yes. He is from Sydney.[ ]
A. Australia
B. Canada
C. Japan
答案:A
因各种原因造成母乳不足或不能按时喂养,可用婴儿配方奶粉喂养,称人工喂养。
设z=sin(x+y)ln(x-y),则().