[填空题]
A person struggles to read b /y8 fdu*/ategy hol: n93 lfdqm) w/hqeh/* seel7cding a book at arm’s length, a distance of 45 $cm$ away (= near point). What power of reading glasses should be prescribed for him, assuming they will be placed 2.0 $cm$ from the eye and he wants to read at the normal near point of 25 $cm$? + D
