According to this passage research in this area is characterized as ______.A.empirically

学历类 职业资格 已帮助 人

According to this passage, research in this area is characterized as ______.

A.empirically observable

B.often impossible to observe directly

C.poorly defined in the research literature to date

D.easier to theorize about than to carry out directly

热搜:medline数据库中to字段是表示非英文文献的原文题名