.three-case-text1 {
    width: 640px;
    height: 145px;
    background-image: url(img/case/energy/tu10.png);
    box-sizing: border-box;
    padding: 25px 0 0 135px;
}

.three-case-text1:hover {

    background-image: url(img/case/energy/tu14.png);

}

.three-case-text2 {
    width: 640px;
    height: 145px;
    background-image: url(img/case/energy/tu11.png);
    box-sizing: border-box;
    padding: 25px 0 0 135px;
}

.three-case-text2:hover {

    background-image: url(img/case/energy/tu15.png);

}

.three-case-text3 {
    width: 640px;
    height: 145px;
    background-image: url(img/case/energy/tu12.png);
    box-sizing: border-box;
    padding: 25px 0 0 135px;
}

.three-case-text3:hover {

    background-image: url(img/case/energy/tu16.png);

}

.three-case-text4 {
    width: 640px;
    height: 145px;
    background-image: url(img/case/energy/tu13.png);
    box-sizing: border-box;
    padding: 25px 0 0 135px;
}

.three-case-text4:hover {
    background-image: url(img/case/energy/tu17.png);

}