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   71075
   SMC and LMC are the best targets of observations to understand a whole
   galaxy. To achieve the goal, studying abundance of interstellar matter,
   hence X-ray observations of middle-aged SNRs, is one of the inevitable
   way. Systematic analysis has been already carried out on ten SNRs in
   the LMC. It revealed for the first time that abundance becomes lower in
   older SNRs, gradually approaching to the LMC mean abundance. We expand
   this fruitful analysis to the SMC, attempting to reveal the SMC
   abundance. We selected four SNRs in the SMC, the estimated ages of
   which are 7700--18000yr. Compared with the LMC samples, these are much
   older, hence we expect that the abundances of them are very close to
   those of the SMC. Three of them have been already observed, and 0049-
   736 is the last sample.
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