Is "là" necessary - i.e., would "?Không có gì tạm thời" work here?
You can omit the "là" here =)
Not without being zapped.
"Không có gì tạm thời." is counted as incorrect. Assuming it is acceptable, it should be added as a possible answer.
Why is the "là" necessary here while it is not in other sentences?
It's not, according to the above. Another DL arbitrary 'zap you!" exercise.
Why do we need một in this sentence. English doesn't have it
Không thứ gì là tạm thời -> why wrong?