Analysis: The ratio of the center of gravity of the triangle to the center line is 1/2, and a straight line can be taken at a special position.

Answer:

Solution:

∫G is the center of gravity of △ABC

∴ Take a straight line DE through G and parallel to BC.

AD = xAB，AE=yAC，

∴x=2/3,y=2/3

The value of 1/x+ 1/y is

=3/2+3/2=3

So the answer is: 3

Comments: This question mainly examines the ratio of the center of gravity of the triangle and the special method to solve multiple-choice questions.

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