虎鲸以黑色为主、黑白相间占少数，而白色虎鲸更是十分罕见。在2000年，研究者惊奇地在阿拉斯加（Alaska）的阿留申群岛（Aleutian Islands）附近发现了一头白色虎鲸，暂且叫它Alaska white orca。2010年，研究者再次在俄罗斯近海岸发现了一头白色虎鲸，我们可以叫它Iceberg white orca。那这两头虎鲸究竟是不是同一头虎鲸
3. 两头虎鲸的年纪对不上。一般来说，人们都是通过背鳍（dorsal fin）的尺寸来判断一头虎鲸的年纪。根据背鳍的大小，当A虎鲸在2000年被发现的时候，被推测为20岁。但是10年后，Iceberg的背鳍尺寸也是20岁。所以，两头虎鲸不可能是同一头虎鲸。
2. 两头虎鲸隔得不算远。虎鲸的哺食模式（Hunting Pattern）分为两种，一种吃哺乳动物（mammal），所以他们经常出没在海岸边。另一种虎鲸喜爱哺食鱼类，所以他们会跟随鱼群的长途迁徙而环游整个海洋。有时候，他们迁徙的路径长达2000英里，所以美国到俄罗斯的区区1500英里根本不算远。
The author points out three reasons to infer that a white orca appeared near Alaska (Alaska) and another white orca sighted in Russia (Iceberg) are two different individuals. However, the lecturer totally overthrows.
First, the reading suggests that coloration differences indicate these two orcas as different individuals. However, the lecturer states algae grown on whale skin varies the skin color from season to season. The more algae, the darker the skin could be.Taking into account of sighting time, the two whales might be the same one.
Second, the author argues the locations of two sightings are 1500 miles apart, which is denied by the professor. Scientists determine that Iceberg can travel over 2000 miles in a hunting group following migrating fishes, which suggests it is not unusual for Iceberg to travel between Alaskan and Russia
Last, the lecturer claims age estimate by the size of dorsal fin is not reliable, which undermines the presumption that dorsal fin keeps growing as the whale ages in the reading. Dorsal fin would stop growing when orca reaches age 20, so Iceberg found in 2010 could be the same whale found in 2000.
假如你马上面临大学毕业要选 final course，会选以前上过课的老师的课还是没有上过课的老师的课程？
If you are going to graduate from the university and have to choose the final course, which professor will you choose. The one you used to sign up for courses or the one you have never learned from before
Professor is one of the considerations that students may take into account for course choosing. Students might hesitate which professor to choose for their final course, the one students used to sign up for courses or the one students have never taken lectures from before. As far as I am concerned, it is undeniable that attending courses taught by familiar professors brings obvious advantages.
Firstly, attending a familiar professor’s lecture saves students’ time. Every professor expresses lecture in a unique approach, either installing theories and ideas or inspiring students to come up with conclusion to specific practice. At the beginning of a lecture taught by a new professor, students are likely to struggle in keeping up with the speed and style. Nevertheless, adjusting to a familiar professor, students skip the adaptation time and receive contents smoothly. In this way, time is saved and a better result is expected.
In addition, learning from a familiar professor is conducive to academic achievement. Task demands vary among professors. Some professors prefer one final examination for the whole course, while others tend to evaluate students by combining class performance, homework, mid-term examination and final examination. Students are more likely to stand out in the whole class because they understand the professor’s expectations and perform accordingly. For example, my friend, Jack, understood his professor’s standard on final report and finished the task perfectly with an extraordinary score.
However, considering from another aspect, learning from a new professor has its own merits. Despite the time cost adapting to teaching style, students can learn more from the professor, such as communication approach, specialized perspectives and specific research outcomes.
Even though students can benefit from both options, I strongly consider choosing lectures from familiar professors more advantageous. Time for senior students is limited, and it can be saved for graduation items and dissertations rather than getting familiar with a new professor.