某井进行跟踪井壁取心,被跟踪峰深度为2541.2M,首次零长为4.6M,第一颗取心深度为2537.4M,第二颗取心深度为2535.8M,则首次上提值为()。
参考答案:8.4M
There _________a book and three pens on my desk just now,but now there is nothing on it.
A. had B. were C. was