My mom suggest that we           eat out for a change this weekend.

should

might

could

would

考查虚拟语气。句意：我妈妈建议我们这周末出去吃饭换换口味。suggest作“建议”时，后面的宾语从句要用虚拟语气（should）+动词原形。故选A项。

True happiness does not            the possession of money, but the joy of achievement.

contribute to

lie in

result in 

add to

考查动词短语辨析。句意：真正的幸福不在于拥有钱，而在于成功的喜悦感。contribute to有助于；lie in 在于；result in 导致；add to增加。结合语境可知，此处指“真正的幸福不在于有多少钱”。故选B项。

It was along the Mississippi River _________ Mark Twain spent much of his childhood.

how

which

that

where

此处构成It was...that...强调句式，句中强调了介词短语along the Mississippi River。故选C。