柳树a棵,比杨树多50棵,杨树和柳树一共有______棵.
a-50+a=2a-50(棵),
答:杨树和柳树一共有有2a-50棵.
故答案为:2a-50.
He is seriously ill. His doctor said he is ___ of death.
A.at the edge
B.on the edge
C.at edge
D.on edge
《劳动法》规定,员工的试用期最长不得超过:()。
A.3个月
B.6个月
C.9个月
D.12个月