题干
Mr. Black___Shanghai in a few days. Do you know when the earliest plane____on Sunday.
A：leaves; takes off
B：is leaving; takes off
C：is leaving; is taking off
D：leaves; is taking off
答案(点此获取答案解析）
B
）轰击Y核生成Z核并放出一个氦核（
），则下面说法正确的是
th