Don't all speak at once!________, please．
Don't all speak at once!________, please．
A.Each at one time
B.Once by one time
C.One for each time
D.One at a time
答案及解析： D
解析：
“不要一起说，一次一个．”one at a time一次一个．
Don't all speak at once!________, please．
A.Each at one time
B.Once by one time
C.One for each time
D.One at a time
答案及解析： D
解析：
“不要一起说，一次一个．”one at a time一次一个．