A:细胞工程
B:酶工程
C:微生物工程
D:基因工程
I hurried to school without ________ breakfast.
图示是某根弹簧的伸长量x与所受拉力F之间的关系图,则该弹簧的劲度系数为____N/cm.
Do you see the sea? The sea is blue,and it is very large(大的).The sea looks beautiful in a sunny day. If(如果)you swim,in the sea,you know that the water is salty(咸的).Do you like the sea?