摘要：欲称出质量是39g的药品.应顺次往天平右盘内添加的砝码是( D ) A.30g.9g B.30g.6g.2g.1g C.20g.10g.4g.3g.2g D.20g.10g.5g.2g.2g

网址：http://m.1010jiajiao.com/timu3_id_3959738[举报]