假如地球的引力减小一半，那么对于漂浮在水面上的船来说，下列说法中正确的是（ ）
A．船受到的重力将不变，船所受的浮力不变
B．船受到的重力将减小，船所受的浮力减小
C．船受到的重力将减小，船所受的浮力不变
D．船受到的重力将不变，船所受的浮力减小
重力是由于地球的吸引而受到的力，故假如地球的引力减小一半，那么对于漂浮在水面上的船的重力一定减小一半；由于船在水中漂浮，所以据漂浮的条件可知，此时的浮力始终等于其重力，故此时重力减小一半，所以其所受的浮力也一定减小一半．
故选B．
Plants are very important living things. Life could not go on if there were no plants. This is 1 plants can make food from air, water and sunlight. Animals and men 2 make food from air, water and sunlight. Animals get their food by eating plants and animals 3 Therefore(因此), animals and men need plants in order to 4 This is the reason(原因) why we find that there are so many plants around us. If you look carefully at the plants around you 5 find that there are many kinds of plants. Some plants are large 6 others are small. Most plants are green.. Some plants have many small leaves. Others have only 7 large leaves. There are many kinds of leaves. Leaves are of 8 shapes(形状) and colors. Leaves are also different in other ways. Some leaves have short leaf stalks(叶茎)while others have long leaf stalks. Still others have 9 stalks at all. The edges(边)of leaves are also different. Some leaves have smooth(光滑的)edges. Some have wave(波状的) edges 10 the teeth of saw(锯).
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