【单选题】According to Adel Safty, ________.
A.
. people should begin to study foreign languages after age 8
B.
. learners who have a friend to help them study a language better
C.
. age has a big effect on people ’ s ability to learn a foreign language
D.
. people ’ s linguistic ability grows with their age and experience
【判断题】J506 and J507 are the very popular low hydrogen electrodes.
【简答题】Please __________ according to your .
【单选题】J422、J506、J507、J502焊条直径4mm焊接电流()。
【判断题】颈外静脉由下颌后静脉前支与耳后静脉在下颌角附近汇合而成。
【判断题】E5016(J506)和E5015(J507)焊条不同之处,是前者含钾较多,正因为如此,两种焊条在同样条件下焊接,E5016(J506)焊条比E5015(J507)焊条容易出氢气孔。( )
【单选题】颈外静脉
D.
在胸锁乳突肌前缘穿深筋膜汇入锁骨下静脉或静脉角
【单选题】J422、J506、J507、J502焊条直径3.2mm焊接电流()。
【单选题】J422、J506、J507、J502焊条直径5mm焊接电流()。
【判断题】科斯定理实际上指出,在交易成本为零的时候,庇古的理论是不必要的。