测定水中硬度时,若冬季水温较低,络合反应速度较慢,可将水样预热()℃后再进行测定
A.15~20
B.30~40
C.40~50
D.50~60
参考答案:B
– Why ask me to take that early bus?
--- Because that bus _______ the 9:30 train at Boston .
A.joins to
B.joins up
C.unites with
D.connects with
为什么强调低速咬入、高速抛出?