零摄氏度的空气
是不可数.When used as a noun, the word training is an uncountable or mass noun, so has no plural form. The word training can also be used as a verb or adjective. He needs some more training. (mass noun) He is training for the Olympics. (present participle of the verb train) He went to two training sessions. (adjective).....................2. You need to attend some important training next month.3. Next month, three kinds of important training will be required of you. Next month, you need to be trained in three important areas.4. Tomorrow, please train the new employees.5. Next week, I shall go to your school to attend Mr. Zhang's class, she teaches very well.
