28. Don't leave Mary by_________. She is only one year old.
A. her B. she C. herself
27. Would you please pass me_________ sugar on the table?
A. a B. the C. /
26. I'm afraid there_________much time left. Let's hurry.
A. isn't B. aren't C. is
(1)如果折痕FG分别与AD、AB交与点F、G(如图1)，，求DE的长；
(2)如果折痕FG分别与CD、AB交与点F、G(如图2)，△AED的外接圆与直线BC相切，
求折痕FG的长．
，求DE的长；
