由于节子本身质地坚硬,其硬度较周围木材打1-1.5倍,因而增大了木材的强度。
参考答案:错
The president made a__speech at the opening ceremony of the sports meeting,which encouraged the sportsmen greatly.
A.vigorous
B.tedious
C.flat
D.harsh
椎前节不包括()。
A.腹腔神经节
B.颈胸神经节
C.主动脉肾节
D.肠系膜上神经节