is standing look可看出是在进行的动作用进行时
is not sleeping
is taking 关键词now
go 关键词always
are ,waiting 与 they are 时态一致
have let's后解原型 祈使
is not singing 与is dancing时态一致
go why not后接原型
are teachers看出为复数
don't like表喜欢 动词非介词
is standing look可看出是在进行的动作用进行时
is not sleeping
is taking 关键词now
go 关键词always
are ,waiting 与 they are 时态一致
have let's后解原型 祈使
is not singing 与is dancing时态一致
go why not后接原型
are teachers看出为复数
don't like表喜欢 动词非介词