马铃薯(四倍体)的细胞在有丝分裂后期和减数第二次分裂后期,染色体组数分别是[ ]
A.4组和1组
B.4组和2组
C.8组和4组
D.8组和2组
答案:C
根据短文内容填空。
Along with jogging and swimming, cycling is one of the best all-round f______ (1) of exercise.
It can help to increase your strength and e______ (2), giving you more efficient muscles (体力) and a
stronger heart. But increasing your strength is not the only a______ (3) of cycling. Because you're not
carrying the w______ (4) of your body on your feet, it's a good form of exercise for people with
p______ (5) feet or backs. However, with all forms of exercise it's important to start s______ (6)
and build up g______ (7). If you have any doubts (疑问) about taking up cycling for health r______ (8),
talk to your doctor and ask his/her a______ (9).
In fact, you should be cycling at least two or three times a week. Don't worry if you begin to lose
your breath. Shortness of breath shows that the exercise is having the right e______ (10).
一5岁女孩,身高82cm,洗澡时发现 * * 增大,无其他异常表现,否认特殊饮食及服药史,骨龄与实际年龄相当,腹腔B超检查正常。最可能的诊断是()
A. * * 肿物
B.中枢性性早熟
C.单纯 * * 早发育
D.正常女童
E.外源性雌激素影响