0.8×0.9≈0.72______．
0.8×0.9=0.72，0.72是0.8与0.9乘积的准确值．所以要用等于号，不能用约等于号．
故答案为：×．
The professor is rich in knowledge and humorous, so we all like to his lecture. [ ]
A. join
B. attend
C. take part in
D. join in
试述糖皮质激素所致的白内障的临床特点。
