If everyone makes a contribution () the environment, the world will become much more beautiful.

单项选择题Do you know().

A．who writing is she to
B．who he is writing to
C．she is writing to whom
D．who is she writing to

单项选择题()is one of the world's most popular water sports.

A．Skating
B．Surfing
C．Baseball
D．Running

单项选择题Hi, Bob! I can't find my history book. () you () it anywhere

A．Did; see
B．Do; see
C．Have; saw
D．Have; seen

单项选择题He () play basketball. But now he likes football very much.

A．use
B．used
C．uses to
D．used to

单项选择题He () his mother a letter at that time.

A．is writing
B．was writing
C．will write
D．has written