题型:判断题 It is only _____ your heart is really in it _____ you can play your best. [ ]A. that; that B. that; when C. when; that D. when; when 查看答案
题型:判断题 Alu因子()。A.是病毒反转录转座子超家族的成员B.每个哺乳动物基因组中有20000-50000个拷贝C.大约长300bpD.包括一个与反转录酶基因有同源的可读框E.被转录F.有LTR 查看答案