s="Python is cool"，可以输出"python"的是 A: print(s[0:7]) B: print(s[:7].lower()) C: print(s[:-8].lower()) D: print(s[-14:-8])

When will the woman’s plane take off? A: 7:30. B: 7:15. C: 8:30. D: 8:15.

When will the tourists be taken to pay a visit to Dr. Sun Yat-sen's former residence A) At 7:30. C) At 8:00. B) At 7:45. D) At 8:30. A: When will the tourists be taken to pay a visit to Dr. Sun Yat-sen's former residence B: At 7:30. C: At 7:45. D: At 8:00. E: At 8:30.

A=4’b1101，B=4’b1011，定义S为S[7:0]，下列正确的是： A: S=A+B=8’b00011001 B: S=A-B=8’b11101000 C: S=A*B=8’b10001111 D: S=A%3=8’b00000010

真空中，光的速度为()m/s。 A: 3.0x10^7 B: 5.0x10^7 C: 3.0x10^8 D: 5.0x10^8

写一个文法G,使其语言为不以0开头的偶数集。 A: G[S]:S→AB|BA→AD|CB→2|4|6|8｜0C→1|3|5||7|9|B B: G[S]:S→AB|BA→AD|CB→1|2|3|4|5|6|7|8|9C→2|4|6|8｜0 C: G[S]:S→AB|BA→AD|CB→2|4|6|8｜0C→1|2|3|4|5|6|7|8|9D→0|C D: G[S]:S→AB|BA→AD|DB→2|4|6|8｜0D→1|2|3|4|5|6|7|8|9|0

What is the reduction in the company’s exports（） A: 7% B: 8% C: 9%

When will the tourists be taken to pay a visit to Dr. Sun Yat-sen's former residence A: At 7:30. B: At 7:45. C: At 8:00. D: At 8:30.

生成: 6 7 8 6 7 8 6 7 8

已知字符串s=“abc",则s的真子串有( )个 A: 7 B: 8 C: 6 D: 5