完形填空。
The white snow is calling you to the hills,lakes and ponds. 1 sports are cool. Keep some important safety tips(安全小贴士)inyour mind before 2 yourself outdoors. Safetytips forall 3 : Always keep yourself warm.Have some training lessons 4 you are new to a sport. Warm up before all sports. Make sure you are in good physical condition (身体状况). When 5 , wear your helmet. Always ski with a friend. 6 a hill far away from roads and parking lots. There should be no rocks or trees. Make sure your bindings are not too tight. 7 skating, never skate by yourself and don't skate too 8 to other people. Check your skating shoes before you 9 . If you skate on lakes or rivers, make sure the 10 is thick enough. Neverskate near open water.
( )1. A. Spring ( )2. A. talking ( )3. A. facts ( )4. A. if ( )5. A. playing ( )6. A. Choose ( )7. A. What ( )8. A. young ( )9. A. clean ( )10. A. place	B. Summer B. fighting B. sports B. or B. skiing B. Stand B. How B. close B. make B. pool	C. Autumn C. enjoying C. clubs C. but C. skating C. Agree C. Why C. tired C. start C. water	D. Winter D. washing D. things D. so D. swimming D. Spend D. When D. happy D. say D. ice

Don't skate on the thin ice, ________ you will fall into the lake.