correct the text by inserting three commas. (note: in this skill, serial commas are not optional.) snails…
correct the text by inserting three commas. (note: in this skill, serial commas are not optional.) snails barnacles coral and sea urchins produce their rigid parts by combining calcium and carbonate ions.
Answer
Brief Explanations:
在列举多个并列事物时，通常在最后一个并列项前用“and”连接，其余并列项之间用逗号隔开。此句中“snails”“barnacles”“coral”是并列的事物，需用逗号隔开。
Answer:
Snails, barnacles, coral, and sea urchins produce their rigid parts by combining calcium and carbonate ions.