[填空题]
How much work must be done to bring three ely q(z/0;rnn4 bccpui 8ectrons f 9n9yrd4tv;g,lau t0q rom a great distance apart to9gqrdu tv0;4nl t 9ay, $1.0 \times10^{-10 }\,m$ from one another (at the corners of an equilateral triangle)? $ \times10^{-18 }\,J$
