2395943 Concentrate, Tom. CK 1 2111747 I'm concentrating. CK 1 2007834 Let's concentrate. CK 1 2245984 I must concentrate. CK 1 2253807 Try to concentrate. CK 1 2237396 Tom must concentrate. CK 1 2387587 I need to concentrate. CK 1 2239757 Tom was concentrating. CK 1 2236949 Tom isn't concentrating. CK 1 2956359 Tom couldn't concentrate. CK 1 2239884 Tom wasn't concentrating. CK 1 2280351 I'm trying to concentrate. CK 1 2544461 You've got to concentrate. CK 1 2953696 We must concentrate on that. CK 1 3161910 I have trouble concentrating. Marissa 1 1026648 Tom concentrated on his work. CK 1 3158425 I have problems concentrating. brad 1 2276381 Tom seems to be concentrating. CK 1 2400191 Tom is concentrating, isn't he? CK 1 2400226 Tom isn't concentrating, is he? CK 1 2540934 I'm having trouble concentrating. CK 1 1095143 Tom couldn't concentrate on his work. CK 1 2400158 Tom doesn't seem to be concentrating. CK 1 2488816 It's hard for me to concentrate today. sharptoothed 1 1025260 Tom has trouble concentrating on one thing. CK 1 20406 Turn off the television. I can't concentrate. CK 1 2400101 Tom always seems to be concentrating on something. CK 1 27858 You should concentrate on one thing and learn to do it well. CK 1 843936 He concentrated on that. J_S 1663814 How can you concentrate? Spamster 2644794 Tom tried to concentrate. CK 2954553 You have to concentrate more. CK 497735 You only need to concentrate. boracasli 310083 She concentrated on one thing. CK 2956855 Tom had trouble concentrating. CK 2958664 Tom was unable to concentrate. CK 303575 He concentrated on his studies. CM 266457 I have difficulty concentrating. CK 275791 All you have to do is to concentrate. CK 286030 I concentrated on what he was saying. CK 1096431 I'm having a hard time concentrating. CK 2007282 Let's concentrate on the job at hand. CK 2956299 Tom closed his eyes and concentrated. CK 2958378 Tom tried to concentrate on his work. CK 402506 He tried to concentrate on the letter. CK 1951422 I can't concentrate while you're here. CK 257254 I concentrated my effort on the study. CK 2539036 You'll have to concentrate a bit more. CK 2957075 Tom is concentrating on the chess game. CK 2958081 Tom seemed to be unable to concentrate. CK