紫露草微核试验中，严格选择处于早期四分体时期的花蕾压片是试验成功的关键。
参考答案：对
读一读，判断正(√)误(×)。
( ) 1. New Year's Day is in January.
( ) 2. Chinese New Year is usually in February.
( ) 3. Christmas is always in December.
( ) 4. You don't go to school in August.
( ) 5. Teachers' Day is in October.
( ) 6. Spring usually starts from June.
简答大气圈的组成。
