1) Spectroscopic dating ======================= In Isobel's paper, the difference between the spectroscopic epoch and the light curve epoch is 3.3 days. I've attached Isobel's paper that was resubmitted last week, where this number is quoted. The "spectroscopic epoch" is defined as the weighted average of the best five fits. The difference between the epoch of the best machting template and photometric epoch has an RMS of 2.5 days for Isobel's set of SNe (see table 3 of Isobel's paper), which is slightly better than the spectroscopic epoch. I believe that the spectroscopic dates listed in Table 2 of your paper are from the best matching template (correct?), so statement you make in the last paragraph of section 2.1, i.e. "usually agree within 2 days", is reasonable. Of the 14 SNe in Isobel's paper, 9 out of 14 agree within two days. You might want to specifically mention that the spectroscopic epoch is the epoch of the best matching template in the caption of Table 1, if that is indeed the case. 2) Regions used for identification ================================== Isobel no longer identifies 4 regions for spectral identification. Instead, she uses three criteria. See section 5 of Isobel's paper. Hence, section 2.2 needs to be modified. I would suggest you cite Lidman et al and Hook et al at the end of the second sentence, keep the 3rd sentence and delete the 4th sentence. Then, start a new paragraph with a modified version of the 5th sentence. We can also use the spectra to identify spectral perculiarities as those found in ... etc. 3) Some miscellaneous points ============================ General. Some times you use "table" and other times you use "Table". This can be cleared up later if you wish. Similarly, sometimes you use Fig. and other times you use figure. Abstract -------- In english, one usually puts a "the" in front of acronyms that are pronounced letter by letter. Hence one would write VLT -> the VLT (but ALMA is just ALMA and not "the ALMA", since we pronounce the entire word and we do not pronounce it letter by letter). There are exceptions to this rule. Introduction ------------ 1st paragraph. The first two sentences are still a bit clumsy. Try ... Type Ia supernovae (SNe Ia) are excellent distance indicators and have been used to show that the expansion of the universe is currently accelerating. In the second sentence, put a comma after "Recently" and place the phrase "aiming ... parameter" between the words "projects" and the words "have started" without commas. Universe and universe. In some cases, you have capitalised the word and some cases you have not. Choose one and stick with it. 2nd paragraph. "some high-redshift SNe Ia" -> "high-redshift SNe Ia" "lower metallicity" -> "lower average metallicity". 3rd paragraph. "The physical origin of these differences are ..." -> The physical origin of these differences is ..." "making difficult" -> "making it difficult" Section 2.1 ----------- 3rd paragraph "to that used in Lidman" -> "to those used in Lidman" Fig. 2 ------ The text in these figures in tiny. The referee will complain. The text for SN 2001gi is partially covered by the spectrum. Section 2.3 ----------- Paragraph 3 "see discussion" -> "see the discussion" Section 3.1 ----------- 2nd paragraph )) -> ) 3rd paragraph, last sentence "dominate" -> "dominates" 4th paragraph Reomove the comma after Li et al. Section 3.2 ----------- 1st paragraph Replace the second "However" with a "but", i.e., "But this does not ..." "as equivalent width" -> "as an equivalent width 2nd paragraph Comma after "papers" Section 3.2.1 ------------- 3rd paragraph "both for" -> "for both" 4th paragraph The last sentence is a bit clumsy. Try "The size of the fitting region is independent of the signal-to-noise ratios of the spectra; however, in low signal-to-noise ratio spectra noise spikes that could bias the continuum fit are avoided." 5th paragraph "In addition the wavelength, of the ..." -> "Additionally, the wavelength of the ..." 7th paragraph "A overcorrection" -> "An overcorrection" Section 3.2.3 ------------- 2nd paragraph A spcae between "F05" and "and." Table 4 caption --------------- A space betwenn Ca II and H&K. Section 3.3 ----------- 1st paragraph Add a space between "F05" and "modeled" Section 3.4 ----------- Remove the ) after Fig. 7. "deviation level" -> "deviations"