A．The moon having not atmosphere B．The moon's having no atmosphere C．For the moon to have no atmosphere D．The moon having no atmosphere
单项选择题It's not difficult to （） the idea that machines can communicate information to us.
A．admit B．receive C．accept D．convince
单项选择题Colour - blind people often find it difficult to （） between blue and green.
A．separate B．distinguish C．compare D．contrast
