TY220推煤机变速杆有哪几个档位？
参考答案：
TY220推土机变速杆有前进一档、前进二档、前进三档、后退一档、后退二档、后退三档和空档共七个档位。
五、单词拼写（共8小题；每小题1分，满分8分）
62. Bob is watching TV and m his sister is doing some washing.
63. At the graduation c , the headmaster gave us an impressive speech.
64. Middle school students are tired out under too much study p .
65. It is e that he is not equal to the job.
66. Most of his p got lost because of the war.
67. There will be an e of the development of our school next week.
68. Who can p what the human being will be like in thousands of years?
69. Without the new communication t , we couldn’t get in touch with each other so easily.
在非严重冻融破坏环境下，C50级以上粉煤灰的烧失量宜小于等于（）。
A、3.0%
B、5.0%
C、8.0%
D、12.0%
