【简答题】根据短文内容选择正确答案。 Here is a new pi cture. There are four boys and three girls in the room. They are all students. The boy on the desk is Jim. The girl near the window is Kate. Jim's sister Jane is on the ...
【单选题】There is a mixed protein solution, and the PI of various proteins is 4.6; 5.0; 5.3; 6.7; 7.3. In electrophoresis, if 4 kinds of swimming are to be made to the positive electrode, the pH of the buffer ...