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).

A．why B．because C．how D．that

A．don’t B．not C．cannot D．can

A．too B．either C．also D．already

A．eat B．live C．have D．get

A．are going to B．may C．certainly D．will

A．when B．yet C．and D．while

A．a little B．a few C．little D．few

A．not B．none C．neither D．no

A．like B．as C．as if D．seem