染色体的长臂和短臂各发生一处断裂,其末端相互交换位置后重接,形成相互易位。( )
参考答案:错
How long ______ you ______ here since you ______ to Beijing?[ ]
A. did; live; came
B. did; live; have come
C. have; lived; came
D. have; lived; have come
PSA吸附时间在调节的过程中,应尽量的延长均压时间,缩短冲洗和顺放时间。