The great thing about the race is that the boys build the cars with their dads, grandfathers, or 15 they choose.
答案：(D) whomever
whomever they choose（無論他們選擇誰）表示男孩們可以和爸爸、爺爺或自己選擇的任何人一起打造賽車，whomever 作為 choose 的受詞代名詞（指人）；whatever／whichever（指物）、wherever（指地方）均不符合此處指「人」的語意。
本題大考中心未公布逐題答對率，以下不談數據，只談觀念。
四個 -ever 長得很像，容易混淆，中文都能說成「不論什麼、不論哪裡、不論哪一個、不論是誰」，很容易憑語感挑；whichever 尤其誘人，因為前面確實列了幾個人可以挑。
又是那三步。第一步找對等連接詞：or。第二步確定它連的是哪兩樣——their dads, grandfathers, or ______，三個並列的成分，前兩個都是「人」。第三步從已知的兩項反推空格：既然前兩項是人，第三項的語意類別也必須是人，wherever（地方）與 whatever（東西）先出局。剩下 whichever 與 whomever，差別在範圍：whichever 是「在限定好的幾個之中挑哪一個」，這一句沒有限定範圍，說的是「或是他們選的任何人」，所以用 whomever。再確認格位：whomever 是動詞 choose 的受詞（they choose whomever），要用受格；而 whomever they choose 整串又當介系詞 with 的受詞。這一類複合關係代名詞自己帶著先行詞，whomever ＝ anyone whom，與 whatever（等於 anything that）屬於同一組。
whatever（不論什麼東西）與 wherever（不論在哪裡）語意類別不對，跟前兩項的「人」並列不起來——並列不只形態要對等，語意類別也要同一類。whichever 要求選擇的範圍是封閉的一組（whichever of the two you like），本句沒有這個前提。
whomever（不論是誰，等於 anyone whom）、whatever（不論什麼，等於 anything that）、whichever（不論哪一個，範圍已限定）、build the cars with（和……一起做車）、quality time（相處的好時光）、It's not about A; it is about B（重點不在 A，而在 B）
The Pinewood Derby is a racing event for Cub Scouts in the Boy Scouts of America. Cub Scouts, with the help of parents, build their own cars from wood, usually from kits 11 a block of pine, plastic wheels, and metal axles.
Cub Master Don Murphy organized the first Pinewood Derby, held May 15, 1953 in Manhattan Beach, California. Murphy's son was too young to participate in the popular Soap Box Derby races, so he 12 the idea of racing miniature wooden cars.
The Scout is given a block of wood made of pine 13 two notches for wheels, four plastic wheels, and four nails. The finished car must use all nine pieces, must not exceed a certain weight, must not exceed a certain length and must fit on the track. Each 14 is able to carve and decorate the car as he chooses.
The great thing about the race is that the boys build the cars with their dads, grandfathers, or 15 they choose. It's not about winning or losing; it is about having the quality time with each other and enjoying a great day with family, friends and smiling faces.