which of the following sentences has the punctuation error?

A. The alarm clock sounded, the students got up quickly.
B. The alarm clock sounded; the students got up quickly.
C. The alarm clock sounded. The students got up quickly.
D. When the alarm clock sounded, the students got up quickly.

An intruductory paragraph should arouse readers' interest and ________ the main idea of the essay.

A. ignore
B. introduce
C. develop
D. emphasize

Which one is not used as a transition word to give examples?

A. for instance
B. such as
C. likewise
D. namely

_________ is the core sentence of a paragraph.

A. Topic sentence
B. The first sentence
C. Supporting sentence
D. Concluding sentence

Write the corresponding word or phrase in the blanks.first of all, on the other hand, furthermore, for example, consequently, on the one handAnother difference among the world's seas and oceans is that the salinity varies in different climate zones. ____1_______, the Baltic Sea in Northern Europe is only-fourth as saline as the Red Sea in the Middle East. There are two reasons for this. _____2_____ in warm climate zones, water evaparates rapidly: therefore, the concentration of salt is greater. Second, the surrounding land is dry and, _______3_____ does not contribute much fresh water to dilute the salty sea water. In cold climate zones, _____4____, water evaporates slowly. ____5_______, the run-off created by melting snow adds a considerable amount of fresh water to dilute the saline sea water.