读一读，写一写。

Sally: Today is Mother's Day. I love my mum. I can buy some flowers for her. What about you, Ken?
Ken: I love my mum too. I can make a photo frame for her. I can say" Happy Mother's Day!" to her. What about you, Linda?
Linda: I like singing. I can sing a song for her. I can give her some lemons.
Today is ____. Sally can ____ for her mum. Ken can ____ for his mum and say "Happy Mother's Day!" to his mum. Linda can ____ for her mum. She can give her mum some lemons too.

观察图，下列说法错误的是

家庭电路中短路或超负荷运行很容易引发火灾，为了避免此类事故的发生，家庭电路中必须安装____；如果家用电器内部导线的绝缘皮破损，人体接触家用电器金属外壳时容易发生触电事故，为防止此类事故的发生，家用电器的金属外壳应该____．

下列关于神经系统组成的叙述，不正确的是(    )

用盐水选种，要求盐水的密度必须为1.1×10³kg/m³．某农场工作人员配制了0.5dm³的盐水，称得其质量为0.6kg．为使配制的盐水符合要求，应再加____（选填“盐”或“水”）____ g．