My mother tells me____ ____ ____ ____on time.
—I since I was 11. Now I am thinking about picking it up again.
—Good for you!
在生活中,手指上会粘上许多细菌.假设:常洗手可以减少手上的细菌数量.甲乙两个同学设计了一个实验,利用牛肉汁固体培养基,灭菌后分别进行细菌培养实验.如图所示,请评价他们的实验方案.
如图,∠3+∠4=180°,∠2=135°,则∠1度数是( )