A:20个卵细胞
B:10个卵细胞和10个极体
C:5个卵细胞和15个极体
D:5个卵细胞和5个极体
— It's dangerous to swim in this river.
—Yes, you are right. The government has ______ people not to swim in it.
读古诗惠崇《惠崇春江晓景》解释下列词语的意思。
①晓
②蒌蒿
③河豚
如图,在一次数学课外实践活动中,小聪在距离旗杆10m的A处测得旗杆顶端B的仰角为60°,测角仪高AD为1m,则旗杆高BC为____m(结果保留根号).